Sleep is something that we all do, or at least we all have done. Despite this, it is still a somewhat mysterious thing. You would think that for something we do for one-third of our lives, we would have a pretty damn good understanding of it. However, this is not really the case. If you asked any random person on the street about sleep, they would likely give you any number of buzzwords related to sleep, but if you prob further and ask about why we need to sleep, how sleep is regulated, what sleep hygiene is or how to get a good night’s sleep, you will likely receive more myths and logical inconsistencies than if you were to talk about something like training or nutrition.
Sleep is “just something we do”, that is until, of course, something goes wrong, and you just can’t sleep. All of a sudden, sleep isn’t something you just do, it is the exact opposite. You toss and turn, and lay there, but that mysterious ether of sleep never engulfs you. So, in this sleep article, we are going to explore sleep a little bit deeper, and hopefully help you to consistently get phenomenal sleep.
The article is laid out as follows, and you can jump to whichever section you feel is most important to you by clicking the link in the Table of Contents:
Table of Contents
We believe in empowerment through education, so we think it is important to have some understanding of the why behind health topics such as sleep. If you understand the why, then the “how” makes a lot more sense. You don’t want to just learn about protocols and hope they work for you. No, you want to build a deeper understanding of the topic so that you can modify the protocols to fit your lifestyle and needs. You certainly don’t need to be an expert, but a little bit of knowledge really does go a long way with this stuff. So we will be discussing some of the science behind sleep and why the basic sleep hygiene practices work, but if you simply want to know what to do with no background information, you can skip all the way down to the Sleep Hygiene section.
If you want more free information on health topics such as sleep, you can follow us on Instagram and YouTube, or listen to the podcast, where we discuss all the little intricacies of improving sleep, training, diet and lifestyle. We also offer coaching, if you need help with your own situation. Finally, if you want to learn how to actually coach nutrition and for a more in-depth discussion of sleep from a coaching perspective, then consider our Nutrition Coach Certification course. If you don’t understand something, or you just need clarification, you can always reach out to us on Instagram or via email.
This article is part of our fundamentals series, where we discuss the key pillars of building “your best self”. Being your best self means you are able to engage with the world how you want to engage with the world and ultimately, accomplish the goals you have. Regardless of what that actually looks like for you, if you can get the pillars set up correctly, you give yourself the best opportunities to accomplish everything you want to in this life. The foundations of the broader society you find yourself in also matter, as do the genetics you were born with or the biology you were born with or acquired (your “biology” could change due to accident or injury, for example, you may have become paralysed, and thus your “biology” has changed), as does your mental and spiritual health, and of course, the health of your local community and support systems. However, much of the foundations are out of our active control, but we can work to set up the pillars as best we can, given the circumstances we find ourselves in. In this article, we discuss sleep and the foundational sleep practices you should engage in to ensure you get good sleep consistently. We have discussed nutrition and stress already, and we will discuss exercise in a future article (you can sign up to the email list to be notified when it is live on-site).
The goal of this article is to provide you with the tools you need to get awesome sleep. However, to do that, we need to dive a bit deeper into what sleep is, the science of sleep and how sleep is regulated. Then we can really dig into the tips you need to improve your sleep (jump to this section if you just want the tips). Let’s dig in!
What Does Sleep Do?
We know an awful lot about sleep, but we don’t know everything. Sleep is a very complex phenomenon and it also crosses many fields of science, which makes it quite difficult to get a comprehensive picture of sleep. It is often discussed as a brain phenomenon, mainly because that is where we have been looking for answers, but it is actually a total body phenomenon. Some animals without a brain (i.e. jellyfish) do actually sleep, and some animals with a brain (i.e. tuna) don’t sleep. Some animals (i.e. dolphins) have very strange sleep patterns (only half of their brain is “asleep” during their sleep, and they alternate this to get “full” sleep). Only looking at the brain also doesn’t give us all the information either, as sleep is actually a full-body phenomenon and many things happen across the body that aren’t measurable if we only look at the brain. Sleep permeates everything in our body, and involves and has effects across many body systems. However, having said all of that, the brain is still heavily involved in sleep and understanding what is going on here will allow us to expand the conversation to other areas of the body. Covering all of what sleep does is simply not going to be possible in this article. However, we don’t need to know it all to help us improve our sleep. The main goal of this article is to give you the tools to improve your sleep, not to make you a sleep scientist. So we are going to go on a whistle-stop tour of what sleep does and how sleep works, so you have some context for why the tools we cover in the foundational sleep hygiene section actually work.
The basic effects of sleep seem to be repair, recovery, consolidation and “setting things up” for the future. I always use the analogy of the body (including the brain) being a factory. Throughout the day, the body is building things and breaking other things down, and in doing all of that, there is some wear and tear on the machinery along with some waste being created. During the night shift (sleep), the factory is cleaned out, any wear and tear on the machines is repaired, and the management sits down and consolidates all of the information that has been accumulated that day and try to plan for the future. I like this analogy because it is easy to understand, and it also gets you thinking that sleep is actually an active process and not just a passive process (i.e. the night shift of the body factory actually involves work being done, rather than nothing occurring at all). It requires energy and if you want to set your factory up well for the future, you need to actually put in some work to ensure the night shift is actually able to do everything they need to do to have the next day be a productive one. What we are trying to do with our sleep hygiene practices is set things up so the night shift has the best chance of doing everything they need to do.
This is a handy metaphor, but it really makes sense once we go through things a little bit more in-depth and we cover how sleep affects different parts of the body and different body systems. What really also helps us to understand what sleep does is to see what happens when sleep isn’t in a good place. However, the things that break first when sleep isn’t in a good place, aren’t necessarily representative of all of the things that sleep does. But it does give us something to work off of. Covering a combination of what goes wrong when sleep isn’t good and then also noting any effects sleep seems to have on different body processes/systems, should give you a pretty good picture of what sleep does. We are going to focus on health, nutrition, exercise and stress, as they are obviously the most relevant to the kind of stuff we care about, but sleep does impact other areas (e.g. productivity, financial health, relationships etc.) that do also feed back onto the stuff we care about at Triage (i.e. your financial health influences your actual health, and sleep impacts your ability to make make money).
Sleep and Health
It is quite hard to cover how good sleep affects the body because it kind of just happens in the background and it almost feels like it isn’t really impacting our health when sleep is good. It is easier to see the impact sleep has on your overall health by discussing what goes wrong when sleep isn’t in a good place. However, it does bear noting that “bad sleep” is a very broad category. Bad sleep could be the occasional hour missed here and there, or it could be chronically missing hours every night, or it could be missing a full night’s sleep (in)frequently, and so on. The health issues that crop up with each of these different situations is likely to be different, but we can still get a general picture of what is going on. I am going to bias the discussion to the effects of chronically missing a few hours of sleep, as that seems to be the most consistent issue people encounter (i.e. they aren’t getting enough sleep most nights, and maybe they are getting a bit more on the weekends).
Before we dive into the effects sleep has on the different systems/processes, I just want to note that sleep really does have its fingers in every pie when it comes to health. As it is implicated in repair and recovery, you can see how that would be something that is pretty important to keeping you healthy. This really does run the gamut from helping you heal little cuts to healing from major injuries, and also repairing the general wear and tear that occurs in daily life for all your body tissues (including your internal organs). Good quality sleep is also vital for the adaptation process. The body doesn’t only repair to where you previously were, it also builds a bit more to help ensure that you are more resilient to the stressors you are likely to encounter in the future. So poor sleep potentially not only reduces your ability to repair and recover to baseline, but it also potentially reduces your ability to adapt and become more resilient. So good quality sleep is a bit of a panacea, and while the analogy is overused, if we could get everything that sleep does into a pill, that pill would be a best seller.
But I don’t want to just leave this as an open-ended, “sleep does everything”. I know you want more specifics, so let’s dig into the effects of sleep on different systems/processes in the body.
Hormonal Health: Poor sleep negatively impacts hormonal health. Poor sleep negatively affects testosterone, estrogen and growth hormone levels. It also tends to lead to an increase in cortisol levels. Poorer hormonal health reduces your vitality, reduces your ability to train hard and adapt to that training, reduces your ability to build muscle and get stronger, and makes getting leaner harder. In general, fertility is also reduced when sleep is poor.
Metabolic Health: Poor sleep increases your risk for diabetes and obesity. A lack of sleep reduces your insulin sensitivity and makes it more likely that you will store calories as fat. Poor sleep also increases the likelihood that this stored fat will be visceral fat, which is the worst kind of fat for health. This is compounded by a lack of sleep leading to a decrease in leptin and an increase in ghrelin, which serves to make you hungrier and thus more likely to overeat.
Heart Health: Poor sleep is associated with an increased risk for heart disease. This is due to the effects on metabolic health, but also because poor sleep is associated with increased blood pressure, a worse lipid (cholesterol) profile, increased oxidation, increased calcification of the blood vessels and reduced repair of general wear and tear (blood vessels, heart etc).
Immune Health: Poor sleep is associated with reduced immune health. With a lack of sleep, your immune system’s ability to fight infections is reduced, and your immune system is somewhat suppressed. It is hard to say how much of an effect sleep has directly on the immune system, but as it acts on other systems that we know affect the immune system (such as the endocrine (hormonal) system), there is reason to believe that poor sleep is reducing immune health.
Inflammation: Poor sleep is associated with increased inflammation. As inflammation is involved in many processes in the body, having an increased level of inflammation due to a lack of sleep is likely not beneficial, especially if you have an inflammatory disease.
Cancer: Poor sleep does increase your risk of cancer, and irregular sleep (as is seen with shift work) is recognised as a carcinogen. A lack of sleep also seems to reduce the effectiveness of cancer treatment too.
Mental Health: Most people are probably aware that poor sleep is associated with poorer mental health outcomes. This is pretty much across the board with mental health issues, from depression to anxiety, and all across the more severe psychiatric issues like schizophrenia. Poor sleep is associated with worse mental health, and suicide and poor sleep seem to be well correlated. Poor sleep seems to also be linked to an increased risk for (and/or increased severity of) many neurodegenerative diseases (notably Parkinson’s disease and dementia).
Mental Performance: This is in the health category because a decrease in mental performance due to poor sleep is associated with an increased risk of injury and death through accidents (most notably car accidents). Poor sleep also decreases your general mental performance and in an increasingly knowledge-based economy, this only serves to reduce your job performance and thus income prospects. Lower income is a risk factor for poorer health outcomes.
Risk of Injury: Poorer sleep is associated with an increased risk of injury, both in everyday life and when engaging in sports and other activities. This could potentially severely reduce your ability to interact with the world (i.e. you could become disabled) or it could even drastically reduce your life span (you may die or your injuries may require more surgeries which increases your risk for infection and other complications).
Now, all of that can be quite scary and I don’t mean for it to be excessively scary, it is just important to understand that poor sleep does have many ramifications for our health. As you can see, poor sleep is associated with many negative health outcomes, and we also didn’t even cover them all. But I just want to remind you that the magnitude of effect is likely different for someone who occasionally gets a little bit less sleep than they would like compared to someone who only sleeps 4 hours a night regularly. Don’t be afraid that just because you got 7.5 hours of sleep last night rather than 8, you are now doomed to ill health. For sure, work to improve your sleep, but don’t think that the body is fragile and can’t handle the occasional bit of sleep deprivation.
Sleep does also have effects on the other pillars of health (diet, exercise and stress), and these pillars also have effects on sleep. And because this is the stuff that we have more control over, it really does help to understand what is going on with these other areas.
Sleep and Diet
Sleep and diet are intrinsically linked, and it seems to be a bit of a bidirectional link. Sleep impacts the diet and the diet impacts sleep. This is just going to be a quick tour of this topic, because this topic is actually quite deep and there is a lot that could be covered.
We discussed metabolism in the article on diet, so I won’t bore you with a discussion of the basics here. Well, to make a long story short, sleep does actually influence our metabolism pretty profoundly. It impacts both our calorie expenditure (calories out) and our calorie intake (calories in). When you sleep less, you end up burning fewer calories during the day at a baseline. Poor sleep results in disturbed hormones, notably thyroid hormones. Lower thyroid output leads to a lower metabolic rate. However, the bigger effect is likely due to the simple fact that being tired likely reduces your energy expenditure by reducing your output during training and your daily life (reduced exercise activity thermogenesis (EAT) and non-exercise activity thermogenesis (NEAT)). Now, the overall impact may not ultimately add up to much, but it is important to realise that your metabolism and calorie expenditure is likely a little bit lower if you are sleep deprived. The effect could be quite large though, especially if sleep deprivation frequently leads to training being skipped due to tiredness or daily NEAT (as measured by steps for example) being very low.
A bigger effect of poor sleep seems to be its effects on influencing your calorie intake. Poor sleep is associated with an increased energy intake (calories in). Most of you have likely experienced this, where you get a poor night of sleep and you just can’t seem to feel full and you are just constantly hungry all day as a result. This is quite common and obviously feeling excessively hungry drastically decreases the likelihood that you will be able to stick to your diet and eat a calorie-appropriate diet long term. Poor sleep is also associated with poorer mood regulation and thus your dietary adherence may also be reduced by virtue of simply feeling worse and turning to food for comfort.
But even if you were able to stick to your calories despite your poor sleep, you will likely be getting less bang for your buck from the diet. You see, a lot of the hormones that are disrupted when sleep is in a bad place, are the hormones that play a role in how the food you eat is used. Carbohydrate metabolism is negatively affected when sleep is bad, pushing you towards a more insulin-resistant state. This isn’t great from a health perspective or a muscle-gain/fat-loss perspective either. Fat metabolism is also disrupted when sleep is poor, which leads to faster storage of fat for later use (a calorie surplus is still required to add to your fat stores over time). But with reduced calorie expenditure and potentially increased food intake due to poor sleep, fat gain is more likely. The fat that is stored in this situation also tends to be visceral fat (the fat stored around your organs), which is the worst type of fat for health. Finally, protein metabolism is also affected by poor sleep. Protein synthesis is reduced (so fewer protein structures (e.g. muscle) are built) and protein degradation is increased (more protein is broken down).
Ultimately, poor sleep leads to reduced muscle anabolism (muscle building), increased fat anabolism (fat storage), increased muscle catabolism (muscle breakdown) and decreased fat catabolism (fat breakdown). While this is a bit of a simplification, and there is obviously a difference between missing an hour of sleep and chronically undersleeping, the general effect is an unfavourable one for those of us who care about our health, performance and body composition.
Getting good quality sleep brings all of these parameters back into a more advantageous position. However, getting more sleep than is needed, (unfortunately) doesn’t confer massive improvements in these various parameters. There is a Goldilocks zone with sleep and getting more sleep than you need isn’t likely to improve your health beyond a certain point, and may just be detrimental to your overall well-being (sleeping for 10+ hours each day does actually eat into your ability to do other things with your life).
Diet and Sleep
Now, we have covered what happens to the diet when sleep is poor, but I did note that this is a bi-directional pathway. What you eat does also affect your sleep. We will cover this a bit more practically in the basic sleep hygiene section, it does make sense to cover it briefly here too.
Protein intake seems to play a role in good quality sleep. Higher protein diets seem to be correlated with improved sleep quality. So it makes sense to ensure that protein intake is sufficient.
Carbohydrates are anecdotally associated with better sleep quality and also with helping people get to sleep faster. There are many potential mechanisms for carbs helping you to fall asleep faster, but it is quite an individualised thing and doesn’t seem to be consistent across people. However, if you notice eating more carbs improves your sleep, then that is obviously a tool in your toolbox to use to improve your sleep.
However, what does seem to consistently lead to poorer sleep is having insufficient fuel to last through the night. Some individuals who are more insulin resistant may find that unless they eat carbs before bed, they will wake up due to dropping blood sugar levels. Similarly, individuals who are eating in a calorie deficit may also experience poorer sleep due to low blood sugar levels, general hunger being higher and potentially also higher stress levels (which are serving to mobilise stored fuel (fat)). Obviously, if you have less fat stores and/or you are in a greater deficit, the sleep disturbances may be more pronounced.
Some people say they sleep better when they eat before bed, however, the research does seem to suggest that eating in the ~2-3 hours before bed isn’t the best practice for improving sleep (or your health). It isn’t a massive issue if you do eat before bed, especially if the vast majority of your lifestyle and sleep practices are dialled in, but it is quite common for sleep quality to be lowered when eating before bed. You may get to sleep more quickly with a belly full of food, but the recovery and repair processes that are supposed to happen when you are asleep can’t occur until the food in your stomach is dealt with. So leaving a bit of a gap between the last meal and sleep makes sense.
Being poorly hydrated also can lead to poorer sleep, which is a tricky one to deal with, as some people find that drinking water in the lead-up to sleep increases the likelihood of them having to get up to urinate during the night. So you have to ensure hydration is in a good place throughout the day, if you want to ensure hydration is sufficient across the night. This is especially important if you live in a warmer climate (or you create a warmer micro-climate with multiple clothing layers, blankets and heating etc.) and this causes you to sweat through the night. Hydrating through the day and then perhaps tapering off your water intake closer to bed likely leads to improved sleep quality.
Coffee intake is also associated with poorer sleep, especially if that coffee intake is later in the day. Caffeine is a stimulant, and thus it is not conducive to high-quality sleep or to helping you get to sleep quickly. The unfortunate thing is that caffeine does actually stay in your system for quite a long time, especially if you are a slow caffeine metaboliser. Even if you can get to sleep, if you have an excessive amount of caffeine in your system, sleep quality will likely be reduced. Generally, consuming less than 400mg of caffeine in a day, and having a cut-off for coffee 9-10 hours before bed is best practice, but even this is associated with some reductions in sleep quality.
Alcohol is another drink that negatively affects sleep. Some people will argue that some alcohol is good for sleep as it helps them to get to sleep a bit faster, but even if this were the case, their sleep quality is still reduced. Even with 1 drink, sleep quality is reduced, so it is best to avoid alcohol if you care about your sleep.
Finally, eating foods that just don’t sit well with your digestive system is likely going to negatively impact your sleep. You are unlikely to get high-quality sleep if your stomach is doing somersaults all night. So choosing foods that sit well with your digestion and don’t leave you feeling gassy, bloated, or generally unwell, is probably a good idea.
Sleep and Exercise
Sleep doesn’t just affect the diet, it does also affect your exercise too. However, similarly to the diet, this is also a bi-directional pathway. In general, poor sleep is associated with worse training outcomes and worse training performance. Most people understand this fairly intuitively, as sleep is important for just generally feeling well-rested and energised. If your sleep is poor and thus you aren’t well rested and energised, well, your performance during exercise is likely to be reduced. Similarly, sleep is important for repair and recovery, and thus, even if you do train hard and your performance is decent, you are getting less repair and recovery from that session when sleep is poor (i.e. it may take you longer to recover from that training session, and this may compound over time into poorer results). However, there is more to this story than just this more intuitive understanding.
Poor sleep results in an altered metabolism (as discussed previously), and this generally results in a pattern of metabolism that is not favourable to exercise performance. Effectively, with a lack of sleep, fat storage is being prioritised and carbs aren’t readily getting into your cells, and thus your preparedness for exercise is reduced. As muscle glycogen is unlikely to be depleted in everyday life, this lower exercise performance may not impact shorter, higher intensity work as much, but longer duration stuff does seem to be quite negatively affected. Naturally enough, if poor sleep is a chronic thing, you will be more likely to notice decreases in performance.
Some people do actually notice a performance increase when they are somewhat sleep deprived, and this is usually only really seen in the shorter duration events (such as lifting weights for low reps or sometimes even sprinting). This is likely due to poor sleep causing an increase in stress hormones which are serving to get you a bit more hyped up for the short duration events. Generally, even in these individuals, you will see that their total exercise volume is reduced with poor sleep in the mix (i.e. they may hit a new 5 rep max personal record, but they find that they can’t do their normal 3-4 sets of each exercise on their program, or they can’t finish the workout in full).
Poor sleep does also lead to greater ratings of perceived exertion, so even doing the same work as last time feels harder. This likely decreases your desire to train, especially if you are chronically getting poor sleep. It is hard to be motivated to train when it feels like you are not only not progressing, but you are actually regressing and things are getting harder, not easier.
Pain tolerance is also reduced with poor sleep, so your ability to push training into productive territory is likely reduced. Again, if the poor sleep is a chronic thing, you will find it difficult to progress if training feels harder than it should, getting closer to failure is just more painful (subjectively you feel it is more painful due to lower pain tolerance) and you experience more pain after the workout too (delayed onset muscle soreness feels more painful than usual).
Cognition and your ability to focus and concentrate are negatively affected when your sleep is poor. Coordination and motor function is also negatively affected when sleep is poor. This makes training effectively much harder, but it also likely also increases your risk of injury. This is especially true of more skill-requiring movements, and even more so when your training is in the less controlled environment of sport. It is also harder to learn and perform complex movements when you are sleep deprived, and this is obviously an issue for those who do sports as their exercise (although it can be somewhat overcome in the gym by simply choosing less complex movements).
With poor sleep, you may not even make it to training, because poor sleep is associated with reduced motivation. This obviously isn’t an ideal situation when consistency is the biggest factor in determining the results you can get from training.
If you do make it to training, you then get hit with poorer recovery from that training. Less muscle growth, less strength acquisition, reduced improvements in cardiovascular function and slower recovery from training overall. Not really ideal at all. Now, of course, there is clearly a difference between a bit of poor sleep one night and chronic sleep deprivation, so the magnitude of this point may not actually be that big of a deal, although it does serve to highlight the fact that sleep is an important part of the adaptation to exercise and the results you get from it. This can also be overcome to some extent by having some form of auto-regulation in your program (we will discuss this more in the foundational sleep hygiene section).
Similar to sleep’s effects on the diet, getting a more optimal amount of sleep leads to a more favourable return from exercise. However, unlike sleep’s effects on the diet, you may actually get a bit more return on investment from exercise if you do sleep a bit more. Nothing extraordinary, but if you are really trying to maximise your returns from exercise, then getting a bit more sleep than is generally recommended may be of benefit.
Now, I realise that discussing the negative effects of poor sleep on exercise (and in general) can be quite off-putting. However, I don’t want you to think that you are doomed to get terrible results from training if your sleep isn’t perfect, and I certainly don’t want to discourage anyone from engaging in exercise just because they can’t get their sleep perfect. In fact, oftentimes, getting some sort of exercise done, does actually improve the negative consequences of poor sleep and exercise is consistently shown to improve sleep. This is because exercise and sleep have a bi-directional thing going on, and your exercise patterns do influence your sleep too.
Exercise and Sleep
Engaging in exercise is actually one of the best things you can do for your sleep, as exercise is consistently associated with improvements in sleep parameters. It tends to improve various sleep parameters, such as reducing the time it takes to get to sleep and improving overall sleep quality. Lifting weights, doing anaerobic training, doing aerobic training, doing sports and pretty much everything in between all seem to have positive effects on sleep parameters. While you can get a bit more granular with exercise type and the exact improvements to sleep you want to illicit, in reality, this isn’t necessary and just exercising in any shape or form does tend to improve sleep (once it is done for sufficient intensity and/or duration). This is both an acute thing (sleep is improved the same day you exercise) and a more chronic thing (the improvements occur over time when you are consistently exercising).
However, it does bear noting that exercising close to bedtime does seem to make it harder to get to sleep for a lot of people. This is both because exercise is generally something that is quite arousing (i.e. it gets you more “hyped up”) and you are quite switched on after training (this is especially the case if you do stuff that is more neurologically demanding, such as heavy lifting or sprinting). But it is also because your body temperature is likely increased after training (and as we will discuss in the section on sleep regulation, this is one of the things that plays a role in getting to and staying asleep). So in general, it isn’t advisable to exercise in the ~2 hours before bedtime. If that is the only time you can exercise, then that isn’t the end of the world, but it would make sense to try and not get overly hyped up for those sessions and also focus on cooling the body down after exercise.
In general, training in the morning or afternoon is likely better for allowing you to really reap all the benefits of the sleep improvements that exercise offers. However, that is likely impractical for the vast majority of you, as that is usually when you have other stuff going on. In the morning you may be rushing to get the children to school and get to work yourself, and then during the day you are at work, and that really only leaves the evening to exercise for a lot of people. This isn’t a huge issue, but if you can leave some time after training to wind down, that will likely lead to better sleep quality than if you are to exercise very close to bedtime. If you are training in the morning and cutting your sleep short to do so, well this is likely less than ideal too. But in the real world, sometimes you have to choose the less than optimal course of action.
What also bears noting is that excessive exercise can also result in poorer sleep. This generally isn’t an issue that most people will have to deal with, but some athletes training multiple hours per week can actually reach a state of overtraining, where their sleep quality will actually decrease and some even develop symptoms of insomnia. Now, this usually isn’t something to worry about, as most people simply don’t exercise enough to ever even get close to this, but it does bear noting that there is a bit of a Goldilocks zone with exercise for sleep too.
Sleep and Stress
Now, somewhat related, and also one of the other pillars, sleep does affect stress. You might also have guessed that this too is a bi-directional pathway. Stress affects sleep, and sleep affects stress. I won’t spend too long on this section as we cover some of this stuff in more depth in the stress article itself.
We often use the analogy of a bucket of water to describe your stress. The bucket gets filled with the various stressors in your life, and the more stress in the bucket, the harder it is to carry and balance. When sleep is poor, you generally have a reduced capacity to handle stress. This is akin to saying, poor sleep reduces the capacity of your bucket and thus it is easier for a smaller amount of stress to fill the bucket. This should be intuitive enough, as most people have likely felt that they just couldn’t handle as much stress when their sleep wasn’t in a good place. Poor sleep is a stressor itself, and thus it takes up space in the bucket. Your baseline stress levels are higher when sleep is poor and unfortunately, that just leaves less room for the other stressors in your life. Poor sleep also reduces your recovery from exposure to stressors, and thus the bucket doesn’t get emptied out as much overnight.
Further to this, poor sleep does actually make it harder to engage with the various stress management practices that serve to reduce stress. It also reduces your cognition and executive function, so you potentially make poorer decisions around stress management practices and most people fail to even identify that a lack of sleep is causing their stress levels to be higher than normal.
Most people also reach for caffeine when their sleep is poorer and caffeine (and other stimulants) are less than ideal when stress is higher. Excessive caffeine consumption also reduces sleep, which only serves to increase stress levels if this pattern continues. Frequently, people also reach for alcohol in this situation too, but unfortunately, alcohol is a stressor itself and it reduces sleep quality. It is very common for people to find themselves in the negative cycle of getting poor sleep, drinking lots of coffee to combat the lack of sleep, then drinking a few glasses of wine or bottles of beer each night to reduce the feelings of stress, and then finding they wake up the next morning in an even worse position because their sleep quality was terrible and the pattern continues.
Stress and Sleep
As noted previously, stress does also affect your sleep. Most of you who have gone through periods of higher stress have likely experienced this in some way. Being highly stressed generally leads to one, some or all of the following issues with sleep:
- An inability to get to sleep easily,
- Frequent wakings throughout the night,
- Waking up early in the morning and being unable to get back to sleep,
- Struggling to get into deeper sleep.
In general, stress has a negative impact on sleep. This is a bit more complex, as stress is a complex thing, and we will cover this more in the article on stress as that will allow you to see that there is more to this. Some level of stress is actually good for sleep, and stressful things like training do lead to improved sleep. However, various types of stress and the timing of that stress do lead to poorer sleep.
What is interesting to note at this stage is that what most people do to improve sleep is actually just stress management. Many of the things we will outline in this article as basic sleep hygiene practices, do actually serve to help with stress management. This is because stress and sleep are very intertwined, but also because a lot of people think they have a sleep issue when in reality they have a stress issue. This isn’t always the case, and working on improving sleep does also help with improving stress, however, when you ask people what they are struggling with, with regard to their sleep, very often they discuss things that are actually stress-related issues. For example, many people will say they struggle to get to sleep because their mind is racing and they are going through a million and one scenarios in their head. While basic sleep hygiene practices can help with this, stress management practices do seem to be more helpful in this case. Of course, the combination of good sleep hygiene and good stress management (and good diet and exercise) practices is even better. As a result, you will see that some of the basic sleep hygiene practices do actually serve to improve stress management, and thus hopefully improve sleep, but in some cases, more comprehensive stress management practices will need to be engaged with to improve sleep.
What Does Sleep Do Summary
So, we covered a lot in this section. I hope this has given you a better picture of what sleep actually does, at least to the stuff we actually care about. When you look online, most of the stuff you find just stops at the “sleep is important for rest and recovery”, which is helpful and certainly true, but it doesn’t really help us to understand what sleep does. I hope that by covering some of the negative consequences of poor sleep you now have a better understanding of what sleep does. However, even this really only scratches the surface of things. But luckily for us, we don’t need to become sleep scientists to get good-quality sleep.
What I do hope you got from this discussion is a better appreciation of how intertwined your sleep, diet, exercise and stress all are. They really do feedback into each other quite a bit, and this is both a blessing and a curse. It is a blessing in so far as, once you start getting some momentum going with good habits and you start improving your sleep, diet, exercise and/or stress management practices, you generally start to see everything else improve, which then makes it easier to continue improving all of the pillars (sleep, diet, exercise and stress management). However, the curse is that if you neglect one of the pillars, you get worse results from the work you are doing on the other things. So you kind of have to work on everything at once, and this can just be quite overwhelming. However, the really important thing to note is that you don’t have to be perfect with everything from the start, and once you start getting some momentum going with the habits you are engaging in to improve one of the pillars, the easier it does get. Focusing on those small wins and looking for that 1% improvement does really add up with this stuff, and over time, it becomes easier and easier to stay in the groove with things. This is where most people fail, they don’t stick with things long enough to build that momentum on their habits, and thus they never get to see that it does get easier once you have some momentum pushing you forward with all of this stuff.
The Sleeping Brain
To understand sleep, it can be really helpful to understand what sleep architecture looks like. Sleep architecture is just the basic pattern of sleep, as measured by polysomnography, but in a more practical kind of way, we can think of it as the pattern of our sleep depth and this can be used as a measure of sleep quality. The reason understanding sleep architecture is important is because it is somewhat more easily measured than a lot of the things you could potentially measure when trying to understand sleep. It also serves as a pretty decent proxy marker for everything else too. When people talk about stuff like deep sleep or light sleep, this is something that can actually be seen in the sleep architecture. While sleeping, it can feel like you are powered off, as you would power off an electronic device, however, this is not the case. While it feels like resting, sleep is actually quite an active process and there are many things going on across the body, and we can see (some of) this activity by measuring brain activity across sleep. We can also see some of the processes that occur across the body by measuring stuff like body temperature, blood pressure, blood glucose levels and even stuff like the number of genital engorgements (i.e. erections of the penis (nocturnal penile tumescence)(often called “morning wood”) or engorgements of the clitoris (nocturnal clitoral tumescence)(often called “morning bean”)) you get across the night. However, we can also make an assumption that if sleep architecture is good, then those other things are likely in a good place too. This isn’t always the case, however, things that would generally disrupt any of these processes will generally also disrupt sleep architecture to some degree.
Now, the thing is, sleep architecture isn’t actually easy to measure. You would have to go to a specialised facility, with specialised equipment and get a sleep study to truly get a good reading of sleep architecture. However, there are a variety of wearable devices these days that can give a “good enough” approximation of sleep architecture.
But what the hell does good sleep architecture actually look like?
The Stages of Sleep
Most people have heard that sleep has various stages to it, and it is these stages of sleep that make up the architecture of sleep. These stages can be differentiated by measuring brain waves and neuronal activity. There are two very distinct stages to sleep, rapid eye movement (REM) sleep and non-REM sleep. Non-REM sleep is further divided into 3 stages (although some would argue that there are four distinct stages), but we will discuss that in a moment. Now, while there is a distinction between the two stages of sleep, it is probably better to view them as a single “block” of sleep. One “block” of sleep is the full cycle from the start of non-REM sleep to the start of the next non-REM sleep cycle. You go through a number of “blocks” of sleep each night, depending on how long you sleep in total.
To really understand this, and to understand why it is important, it helps to actually go through step-wise what is happening when you go to sleep.
When you are falling asleep, perhaps you are lying on your bed and your eyes are feeling heavy, is when you enter into stage 1 non-REM sleep. This change over from being awake, to light sleep, only really lasts a few minutes. You likely have experienced being awoken during this stage (by a noise or something) and you have this kind of hazy memory of falling asleep. During this stage, your heart rate and breathing begin to slow down and your eye movements reduce. Your muscles relax and you may experience some muscle twitches (hypnic jerks) during this stage. The brain waves also slow down, into a more alpha brain wave pattern.
After this, you enter stage 2. This is where sleep really begins, it is light sleep for sure, but it is deeper than stage 1 and waking someone up during this stage is a little bit more difficult. Someone woken during this stage will likely feel like they were actually asleep, rather than only feeling like they were still kind of drifting in and out of sleep (as they may feel during stage 1). Heart rate continues to drop, as does body temperature, and eye movements cease. This is where you really start seeing the whole body effects of sleep, as metabolism slows down during this time (as cellular activity reduces). Brain waves become slower and larger than in stage 1. This stage lasts ~20 minutes before transitioning to the next stage, although across your sleep, you will actually spend a large portion of your sleep in this stage.
Stage 3 is the sleep we want the most. This stage generally occurs about 35-45 minutes after you fall asleep, and you spend more time in this stage during the first half of the night, with further sleep cycles spending less time in this stage. This is because this stage is the deep, restorative sleep that leaves you rejuvenated when you awaken (unless of course you are awakened during it, in that case, you will feel groggy/disorientated). Naturally enough, as you have repaired/restored the body, less needs to be done later during the subsequent sleep stages. However, individuals engaged in progressive and challenging training routines may notice that their deep sleep remains quite long through the subsequent sleep stages, as they simply have more repair/restoration demands. These individuals may also notice they simply need more sleep too (as both their restorative sleep stages are likely to be longer, and they may need more of them, and this is why athletes are advised to generally get more sleep than the average person). This stage was previously divided into two-stage (3 and 4), and while there are potentially some differences across this stage, most research categorises this as a singular stage these days. During this stage, your heartbeat and breathing slow to their slowest levels. Your muscles relax even further, and you see an increased supply of blood to your muscles. Tissue growth and repair occur at this stage. Certain hormones are released, and restoration of the body occurs. Brain waves become even slower and larger at this stage, transitioning into what are called delta waves. As a result, the outside world is nearly completely blocked out. Most sleeping individuals in this stage will be difficult to awaken, although it is also at this stage that certain parasomnias (such as sleep-walking and sleep-talking) occur, which can make it seem like people are more awake than they are. For our purposes, the main thing you want to understand about this stage is that it is the most restorative of the stages of sleep. So for those interested in health and fitness, we want to ensure this stage of sleep is maximised. However, we simply can’t forget the other stages’ importance, because they all have a role to play.
Finally, we reach the next stage of sleep, REM sleep. You first enter REM sleep about 90 minutes after falling asleep. The length of time you spend in REM is the inverse of the length of time you generally spend in stage 3 NREM sleep. So as the night progresses, you spend more and more time in REM sleep, and less time in stage 3 NREM sleep. This stage of sleep is the easiest to visually assess whether someone is in it because their eyes rapidly move (hence the rapid eye movement (REM) name). But you would also notice someone reach this stage due to their breathing becoming faster and more irregular than the previously slow and regular breathing of the last few stages. Heart rate and blood pressure also rise and are often at levels that would be seen when awake. Body temperature is also more variable than during the previous stages of sleep. Your muscles (except for those involved in breathing/heart beating, and of course your eyes) are effectively “turned off” during REM sleep, leaving your body in a state of temporary paralysis. This is quite important, as during REM sleep, your brain waves resemble those seen during waking and it is during this stage of sleep that most of your dreaming will be done. The rapid eye movement that is seen during this stage is hypothesised to be in response to the visual aspects of dreams, so the eye muscles are clearly not being inhibited. Your brain is effectively shutting off your body, so you don’t actually act out your dreams. This inhibition of movement is a carefully orchestrated phenomenon, although sometimes there is some lag and you can wake up mentally before you wake up physically, and this sleep paralysis can be quite frightening as you can’t move your body. You are also potentially still in this semi-dream state, so you can dream all kinds of scary things in response to not being able to move your body. This inhibition of the body can also just not occur, and this can result in phenomena such as sleep-walking (which can, naturally enough, be quite dangerous to do) but even sleep-killing (people have used this as a defence in court and not been charged with murder as a result). This muscle inhibition can also work against you, especially as a child, and is partially responsible for bed-wetting. The signals between the muscles preventing you from urinating, and the signal of muscle inhibition do need to be fine-tuned. Unfortunately, this results in children (and often times drunk individuals) wetting the bed. This is usually accompanied by dreams about urinating. This is interesting, especially when we consider the role of REM sleep.
REM sleep brain activity is seen in areas of the brain that are involved in storing memories, learning and mood (although Stage 3 NREM is also crucial to all of this too). Dreaming may be part of the process of interpreting the information you have been exposed to during the day, and then storing that information away. This information interpreting and sorting applies to both “factual” and “emotional” information. I always think of REM sleep as your “sense-making” time. It is the time when you make sense of the world, and this is often why you will see people say that an idea/concept/invention/musical piece/poem/story etc came to them fully formed in a dream. You were just putting together all the information you had already gathered, and making sense of it. This is why it is very important to get good quality sleep. Those who don’t get REM sleep are not as likely to access these deeper insights, but they also just aren’t good at storing memories. They don’t make good decisions, and they are generally not as emotionally stable as those that get good sleep. It does bear pointing out though that all of the sleep stages are important for proper learning, memory and (physical and mental) performance. So while REM is often quoted as doing the job of information interpreting and memory consolidation, it does this against the backdrop of the other stages of sleep.
Sleep isn’t fixed across your life though, and it does vary quite a lot both between individuals and in a specific individual. As you age, you will usually get less REM sleep. This isn’t a guarantee though, as elderly individuals who engage in cognitively demanding activities seem to have more REM sleep. Being active also changes sleep architecture in the elderly, and is generally associated with improved sleep quality. You may also notice that depending on the activities you have been engaging in throughout the day, you do actually acutely change the architecture of your sleep. For example, if you go on a hike in an unfamiliar area, you may have altered sleep architecture, as you are working through all of the things you have seen/experienced throughout the day and you are also recovering from the hike itself. So we shouldn’t view sleep architecture as a fixed thing, and very often we are just talking in generalities when discussing sleep architecture, and even if we get a better picture of our own unique sleep architecture, this is still likely to change day to day and across our lifetime.
Now, I realise that this has been a bit abstract and it can be quite hard to piece together. However, what really helps to get a grasp of this is viewing sleep architecture across the night, rather than just in smaller segments. Sleep progresses in a stepwise manner from non-REM stage 1, to non-REM stage 2, to non-REM stage 3, to REM sleep (initially). This progression takes roughly 90 minutes, from when you are falling asleep to when you enter REM sleep (let’s call this a sleep block). Then a sleep block, from the end of the REM phase to the end of the next REM phase, proceeds to cycle on a roughly 80-120 minute schedule. This is both individual and not static. It is not static across a night (i.e. some phases may be 80 minutes, while some may be 120 minutes (although it isn’t as likely that there will be that big of a spread), and later sleep blocks do appear to be longer than the blocks earlier in the night), not static across a lifetime (i.e. what you experience as a child will be different than as a 90-year-old), and it is also dependent on what you actually do during the wake period (i.e. if you are in a hyper-stimulating novel environment and also engaging in strenuous activity while you are there, your sleep blocks are likely to be different than if you were lying in bed all day doing something you do every single day and have already “mastered” from a neurological perspective). This does have some practical relevance later on though, so do keep it in mind. It should also be kept in mind that these do get somewhat entrained to the daily cycle, and this is especially the case the more consistent your daily schedule is (especially your sleep and wake times).
What can be quite confusing initially when learning about sleep is the fact that the length of the phases changes across the night. What you need to keep in mind is that as the night progresses, your REM sleep increases, but your stage 3 sleep decreases. This is easy enough to understand if you think of stage 3 sleep like recharging a battery. After the battery is full, there is less need to charge it. The later stage 3 sleeps of the night are just topping the battery up any small percentage drops that were lost during the time between the last charge. This isn’t exactly analogous, but it helps to understand the basic premise as to why stage 3 reduces. It also helps to think of REM sleep as “active sleep”, as you are dreaming and your brain activity is actually quite similar to “active” brain activity. So the battery needs to be full to enter this stage of sleep, and it uses some energy to engage in it. You only have a set time period to both charge the battery and engage in active sleep, so the first time through, you need to charge the battery up more, but once you have charged it up, the subsequent times, you only need to top up the battery a little bit and thus it takes less time (i.e. less time in stage 3), but you get more active time (REM). Again, not a perfect analogy, as both stages do much more, but it does help me remember these facts about the sleep stages.
What is also a little confusing is the fact that in most discussions about sleep, REM is often discussed straight after NREM stage 3, and quite often the discussion just stops at REM sleep and then doesn’t tell you what happens next. You can be left thinking that sleep proceeds as NREM stages 1-3, then REM and back to stage 1, but this is not the case. The progression is actually, stage 1, to stage 2, to stage 3, to REM, then back down stepwise to deep sleep, then usually stepwise back out, and then stepwise up and down again (but not getting quite as deep) until you awaken. The below image illustrates this more clearly.
It is more accurate to think of the progression of sleep from light sleep, stepwise down to deep sleep, and then stepwise back out to REM sleep. This, of course, makes sense, as going from your deepest sleep to your lightest sleep (although REM is still a sleep stage you will awaken groggily from) in an instant doesn’t make that much sense. Although it does somewhat happen like that for the first sleep cycle, it is more likely that this is just a faster progression from deep to light, and in reality, it is still stepwise. It is also important to notice that sleep architecture changes across the night, as stated previously. As the night progresses, you get less deep sleep and more REM sleep. By the end of the night, you are pretty much cycling between light NREM sleep and REM sleep.
You generally get about 4 to 5 sleep blocks done in a night, depending on how long you are actually sleeping. A single sleep block lasts about 80-120 minutes. Again, depending on what you have been doing during the wake time, what stage of life you are at, and how your previous nights of sleep have been.
Now, that (hopefully) gives you a better glimpse into what happens when you sleep, at least as far as the basic things that are happening at the brain level. This is important for helping you improve your sleep, as many of the sleep tracking devices will give you some sort of information on your sleep architecture and without the context of what sleep architecture should actually look like, you may not know how to interpret that information. However, what we really care about, for this discussion at least, is what actually regulates sleep and then what should we be doing to ensure high-quality sleep each night!
Sleep Regulation
Understanding how sleep is regulated is really important for helping us to understand how to adjust our habits to ensure high-quality sleep regularly. If we know what is regulating our sleep, we can try to influence this to improve our sleep. We have been discussing the brain a lot, but the brain is not just one homogenous unit, it is actually separated into relatively distinct areas with specialised functions. So, to really dig into sleep, we just have to briefly familiarise ourselves with some of the areas of the brain and this will be incredibly helpful in understanding sleep regulation.
The first area of the brain involved in sleep that we need to touch on is the hypothalamus. Now, the hypothalamus is quite important to remember with regard to sleep because it is part of the hypothalamus-pituitary-gonadal axis, and is heavily involved in quite a lot that we care about in the context of being healthy and fit humans. In this context, the hypothalamus is involved in controlling sleep, because within the hypothalamus is the suprachiasmatic nucleus (SCN). The SCN is involved in syncing your sleep-wake schedule to the environment.
The next area of the brain that is important to understand is the brain stem, which serves to communicate what the hypothalamus says to the rest of the brain. In response to the cueing of the hypothalamus, the brain stem produces neurotransmitters such as GABA, which serve to reduce wakefulness (probably more accurate to say it dampens arousal) in the rest of the brain. Areas of the brain stem also play a role in relaxing the muscles of the body during stages of sleep, such as REM (this is why you don’t act out your dreams and why you sometimes wake up with sleep paralysis).
The pineal gland is also important to consider when discussing sleep. It is a small gland within the two brain hemispheres that receives the signals from the SCN and produces melatonin in response. The communication between the SCN and the pineal gland is quite important, and the way the daily light-darkness cycle influences melatonin secretion does provide us with some very actionable information we can use to get better sleep quality and quantity (which we will discuss in the sleep hygiene section).
The thalamus is also important during sleep, as it generally communicates the information you get from your senses to the cerebral cortex, and during sleep, it goes quiet. However, during REM sleep, it does become active again (which is why you get all the sights, sounds, and other senses during your dreams, but also why, if your alarm goes off during REM sleep, it can often become part of the dream, as you are able to take in external stimuli). Now, it is important to keep in mind that the thalamus does go quiet during portions of sleep, as this means the cerebral cortex doesn’t have that stream of information coming in and thus is able to do the “repairs” it needs to do. These repairs include consolidating all the information you have received from your senses during the day, so in other words, it is during these times that you consolidate your memory. The amygdala also plays a role during REM sleep, and as it is generally considered to be the area of the brain involved in processing emotions, you can imagine that REM sleep is required to truly consolidate the totality of your daily lived experiences. But both REM and non-REM sleep do appear to be required for true memory consolidation.
The basal forebrain is also involved in sleep and wakefulness, along with the midbrain also playing a role in wakefulness. This area is important to keep in mind, as it is here that your brain releases acetylcholine in response to adenosine levels. Acetylcholine plays a role in wakefulness, and its levels play a role in sleep drive. We will come back to this later on, as caffeine interacts with this system of adenosine release, and gives us some information we can use to engage in better practices for better sleep quality and quantity.
Now that you have a better picture of the brain as it relates to sleep, we can really dig into sleep regulation.
Mechanisms of Sleep Regulation
What causes you to sleep? Most people don’t stop to think about what actually regulates their sleep and wake cycle, it is just something you do every day. Have you ever wondered why you get tired? Ever wonder why jet lag is a thing? Wonder why caffeine keeps you feeling more awake? Wondered why watching TV or playing on your phone late at night seems to keep you more awake? It is all down to sleep regulation.
There are two mechanisms that regulate our sleep, and these are circadian rhythm and what is often called sleep-wake homeostasis (which to an extent, utilises circadian rhythm-related stuff too, so I wouldn’t necessarily view them as completely different things). We will cover circadian rhythm first and then go through sleep-wake homeostasis.
Circadian Rhythms
The term circadian comes from the Latin, “circa” and “diem”, which mean “around” and “day”, respectively. So circadian just means “around the day”, and adding on rhythm, well it means around a daily rhythm. It is the term used to describe the phenomenon that certain things seem to occur on a schedule that follows the solar cycle. Most of you are likely awake during the day and then sleep during the night, and we have evolved to follow this schedule. We are evolved to become “entrained” to this daily schedule, and we use a few external signals of the time of day to set our internal “body clocks”. Just like your phone uses the internet to set itself to the correct time, your body sets its clocks by virtue of inputs from the solar cycle. Now, as you can imagine, this isn’t perfect. Your body does its best to align to the 24-hour day, but it actually generally sets its time to a ~24.2 hour day. Close enough, but not perfect. Your internal clocks can also come out of alignment with the solar cycle if you remove or modify the expected inputs that your body uses to set its time.
Now, you may be wondering, “why the hell does my body need to know the time?”, and this is a good question. The answer is pretty straightforward though. Different things need to happen at different times within the body, and some of them need to occur regularly and some have to occur in a certain sequence and thus have to be ordered to occur at specific times. For example, your body releases certain hormones and signals to wake you up in the morning. If these systems were activated when you were trying to sleep, that wouldn’t be appropriate and you would find it quite difficult to get to sleep as a result.
While there are multiple clocks in the body, they are all set against the master clock. So we really only need to understand the variables that go into regulating the master clock, as all other clocks set themselves against that. So what is this master clock?
The Circadian Master Clock
While it is helpful as an analogy, you don’t actually have a real clock within the body. What you do have is a hypothalamus, and more specifically, a suprachiasmatic nucleus (SCN). The SCN is located directly above the optic chiasm (basically where the optic nerve interacts with the brain). The hypothalamus and pineal gland send signals to the rest of the body to help your body set its times, and it does this based on the signals the SCN is getting (and communicating to the other brain areas) about what time it is. The other peripheral clocks around the body receive the message and set their time based on what the SCN says. So the SCN is the master clock that all the other clocks are setting their time to.
So what we really care about from a sleep regulation standpoint is, what are the signals that influence the SCN? How does it know what time it is, and can we use this information to get it to know when it is bedtime (and thus help us to get to sleep faster and more consistently)?
Imagine you had to estimate the time from just the environment. What would you use? You would more than likely look around and try to estimate the time of day based on the position of the sun in the sky. When the sun is higher in the sky, it is usually closer to the middle of the day. When the sun is lower, it is usually morning or evening. If you know what hemisphere of the planet you are on, you would be able to tell if it was morning or evening, or alternatively, if you followed the movement of the sun over time, you would see if it was going up or going down (and thus you would know if it was morning or evening).
But you also might use the temperature to identify whether it is morning or evening (and indeed what time of day it is). When the sun is down, the temperature is generally cooler than when the sun is up. In the morning times, the sun’s rays haven’t had sufficient time to warm things up, so it is generally still quite cold. During the middle of the day, that is generally when the temperature starts to reach its warmest, and this usually extends a few hours as the suns rays have spent more time heating up the environment. As the sun sets, the temperature is still generally quite warm, until a few hours after the sun sets, as the environment takes some time to cool down. So temperature can also be used to inform you of the time of day, but it isn’t as easy to interpret as daylight, as you need more context.
Funnily enough, the body also uses both of these very same inputs to regulate its internal clocks.
Variables That Regulate Circadian Rhythm: Light
As we are trying to set the master clock to the solar cycle, the most obvious environmental cue that is used is the sunlight the sun produces. Your master clock uses sunlight to tell the time. But how does the SCN, which is in the brain, know what sunlight looks like? Well, as mentioned previously, the SCN is located right above the optic chiasm, and this allows the eyes to relay the signal of the sunlight to the brain. But this process isn’t like a light switch, where it is turning on or off depending on whether sunlight is detected or not, instead, it is actually analysing the specific wavelengths and intensity of light that enters the eye. Sunlight has different properties across the day, based on the relative position of the Earth and how the light interacts with the atmosphere. The intensity of the sunlight changes across the day, and the angle through which the sunlight travels through the atmosphere changes the spectrum of the light (there are more blue wavelengths of light during the actual day, and more red wavelengths very early and later in the day (and as a result, you have probably seen some intense red-shifted sun rises and sunsets)).
Your eyes take in the light, then relay the signal to the SCN, which then uses this information to “set the time”. The SCN then relays this information to the rest of the hypothalamus and the pineal gland. In response to being told that it is coming up to bedtime (it is getting dark out), the pineal gland secretes melatonin. Melatonin is used to signal to the body (and brain) that it is bedtime. This light-dependent melatonin secretion is a key player in sleep regulation. Blue wavelengths of light will serve to reduce or eliminate melatonin secretion, as that is what the SCN interprets as a daytime signal.
So light is one of the key variables that serve to regulate our sleep. This is really important, as it is one of the key things we can use to improve our sleep (and we will discuss this more in the sleep hygiene section).
Variables That Regulate Circadian Rhythm: Temperature
As I mentioned earlier, if you were trying to figure out what time of day it was, you may be able to deduce roughly what time of day it was by virtue of the temperature. Well, your body clocks can do the same, but just like it would be for you, using this method isn’t as accurate as using light, but it can be used as additional information to help fine-tune the information from the light.
Now, how does this tie into sleep? Well, as some of you have likely experienced before, when the temperature is out of a specific range, it can be quite difficult to get to sleep and stay asleep. Trying to get to sleep when it is freezing cold or roasting hot can be incredibly difficult, and you have likely experienced waking up in the middle of the night due to it being too warm or too cold. So, temperature clearly does play a role in regulating sleep. The reason behind this is that the hypothalamus is involved in regulating body temperature, and as you will remember, this is where the SCN (master clock) is located.
Your body temperature does actually follow a circadian rhythm, and this is largely due to changes in metabolism and hormonal output across the day (as dictated by the SCN). Body temperature generally rises in the morning, and then lowers as you get closer to bedtime. The SCN tells the hypothalamus what time it is, and the hypothalamus then signals to cause an increase in cortisol in the morning to wake you up and this serves to warm the body up. As cortisol drops off later in the day, body temperature reduces and this is part of the signalling that serves to get you to sleep. But the system does work both ways. However, what is interesting is that temperature isn’t necessarily changing the time the SCN thinks it is, but rather, it is influencing the peripheral clocks. The rest of the body can have their clocks pulled out of line with the master clock by changes in temperature. Changes in body temperature can serve to cause the peripheral clocks to somewhat ignore the master clock. This does actually have some pretty significant implications for our basic diet and exercise habits, and our basic sleep hygiene habits too. This can be a bit abstract, but a few examples can really help to illustrate the relationship here.
Most obviously, this can be seen when the room temperature is too warm or too cold. In either case, you can find it difficult to wind down and get to sleep, and if you do, you can find that your sleep quality is quite poor and you awaken frequently.
Eating food has a thermic effect, and serves to raise body temperature, which can make it difficult to get to sleep (this is one of the reasons we generally recommend leaving some time between your last meal and sleep).
However, eating too few calories can cause cortisol to rise to help mobilise stored fuel, and this can serve to raise body temperature and cause you to find it difficult to get to sleep and/or stay asleep. You see this a lot in bodybuilders, as they get closer to competition, their sleep gets progressively worse due to calories being low along with stored fuel (fat) also being low.
Drinking coffee (or taking any stimulant) can also raise body temperature, which plays a role in disrupting sleep (along with the other effects of the stimulants).
Exercise also generally raises body temperature, and causes the secretion of cortisol (especially if the training is excessive), and thus can cause you to struggle to get to sleep if you perform it too close to bedtime.
You may think that you can hack the system by having a cold shower/bath before bed, as this should cool the body down and thus improve sleep. However, this can cause the body temperature to drop too low and the body then actually has to warm itself up, which can result in disrupted sleep. It can also cause vasoconstriction (narrowing of the blood vessels), which can make it difficult for you to effectively thermoregulate and cool down during sleep. So having a warm shower/bath may actually be more beneficial (as this causes your body to increase processes that serve to cool the body down, such as increasing vasodilation which allows you to lose more heat to the environment as a result).
Stress also plays into this, as being stressed raises cortisol and thus can raise body temperature, which can reduce your ability to get to sleep (stress does also have other mechanisms by which it impacts sleep).
Now, before I move on, temperature does have an impact on your ability to get to sleep and stay asleep, and it is certainly important to understand as it plays a role in many of our basic sleep hygiene habits. However, body temperature is generally quite well regulated and we don’t need to excessively concern ourselves with managing it. While there can be much larger swings, generally, we don’t have to think about managing this too much, at least in the developed world. We can certainly make better choices to ensure that our body temperature (and the environment temperature i.e. the room we are sleeping in) are at a level conducive to sleep, but we don’t need to excessively worry if there is some small degree of body temperature variability.
Chronotypes
As we are discussing circadian rhythm, and specifically around sleep circadian rhythms, the conversation of chronotypes invariably comes up. Your chronotype is simply the sub-category you fall into describing how your body interacts with the solar cycle. For example, you may be a “morning person” (often called a “morning lark” in the literature) and find you are most awake then. Alternatively, you may be more of a “night owl”, and find that you are at your best later in the day. This is an evolved trait, as humans are hyper-social communal animals, having different members of the group more awake at different times ensures greater survivability as there is an increased likelihood that someone will be awake to alert everyone else or fend off a threat (or alert the others).
It is rare to have a perfect textbook chronotype (i.e. to be either end of the extreme), and very often people will self-identify as night owls when in reality, they just have very poor sleep hygiene. However, you may find that you just perform better in the morning or the evening, and this is completely normal. You may find you prefer getting up a little bit later, and going to sleep a bit later, or vice versa. Unfortunately, the world is generally set up to better align with morning people, with work/education generally starting at 8-9 am and ending at 5-6 pm. So if you are someone who is truly a night owl, you may find that you are always in conflict with your work schedule and this can just be difficult to overcome. This is likely why many people who identify as night owls end up in jobs in areas like the tech industry where they are doing stuff like computer coding and aren’t required to follow a 9-5 schedule and can work on a more flexible schedule.
There is a lot more that we could discuss about chronotypes (and there is a whole field of chronobiology that we could dig into), but it ultimately doesn’t actually change our recommendations all that much. The basic sleep hygiene practices are just a starting point, and they are to be refined based on how you react in the real world. Having said this, I would caution you from chronotyping yourself, as you will most likely end up coming to the conclusion that you are a night owl. This is very often just the result of poor sleep hygiene, and most people are actually mostly aligned with the “normal” waking day.
Finally, I would also like to say that your chronotype does likely change across your life. This is most evident in children and teenagers. Very often they will have sleep patterns that are completely different than what they eventually end up having when they are adults. Teenagers are notorious for staying up late and then struggling to get up in the morning. This is likely a combination of poor sleep hygiene as well as a chronotype that is more shifted towards the night owl type. The elderly also often display a chronotype that is different than what they displayed throughout their life. The elderly very often wake up extremely early in the day, and then also fall asleep earlier in the day. There may be an evolutionary reason for this, again, to ensure that there is always someone awake throughout the day, but regardless of the reasoning, the point remains that your chronotype is likely to change across your life.
Now, I realise that has been quite a lot of information, and you may actually have forgotten that we were discussing the mechanisms of sleep regulation and that circadian rhythms aren’t the only thing responsible for regulating our sleep. There is another mechanism that regulates our sleep, and that is sleep-wake homeostasis.
Sleep-Wake Homeostasis
Sleep-wake homeostasis is unlikely to be something you discuss casually with your mates, but it does play a role in regulating our sleep. Circadian rhythms aren’t the only thing that serve to regulate your sleep, your body does also keeps track of its sleep needs and how much sleep you have gotten. When you are awake, you build up a “sleep drive” (sometimes called sleep pressure) and the longer you are awake, the bigger this sleep drive gets. When you sleep, the sleep drive decreases. The analogy I always use is a kettle boiling. When you are awake, you boil the kettle, and after a certain time period, that kettle begins to really start boiling and bubbling away. This is your signal to take the kettle off the heat (i.e. go to bed). This analogy is quite helpful because it also helps to illustrate common things that you may have experienced before.
Firstly, having a nap serves to reduce your sleep drive and thus you may struggle to get to sleep later that day. If you take the kettle off the heat and let it cool down (i.e. you have a nap), and if you then place it back on the heat (i.e. you are awake) it is going to take some time before it heats up again (i.e. it takes time to build up your sleep drive). So having a nap closer to your normal bedtime means that you have less sleep drive built up, and thus you may struggle to get to sleep. You may then find that you aren’t able to get enough sleep the night of the nap, as you likely have a mandatory wake time (i.e. you have to get up for work) and thus, you are even more tired the next day, as you weren’t able to clear away all of that built up sleep drive. This can very easily become a vicious cycle were you feel like you have to nap each day because you are never able to get enough sleep because you struggle to get to sleep. However, if you do have a nap earlier in the day, you may be able to get to sleep at your normal time with little issue (because you have more time to build up sleep drive (boil the kettle)), but this isn’t always the case.
Secondly, if you stay awake all night and don’t sleep, it isn’t circadian rhythm that is driving you to sleep, it is sleep-wake homeostasis. You have been boiling the kettle for a long time, and you need to take it off and let the water cool down. Sleep drive has built up to a point where you are completely uncoupled from your normal circadian rhythms and your body is signalling you to go to sleep ASAP.
Thirdly, the analogy is helpful because it also helps to explain what happens when you consistently under-sleep. If you are always starting with a kettle with warmer water in it (because you haven’t given it sufficient time to cool down (i.e. you haven’t slept enough)), then you are going to feel that sleep drive much sooner the next day and likely more and more intensely as the sleep debt builds up across the week. You can let some of the water cool by getting more sleep on the weekends, but all of this does feedback into circadian rhythms. Your sleep-wake homeostasis can serve to reinforce your circadian rhythms or it can serve to pull them out of alignment, depending on your day-to-day habits.
How Does Sleep-Wake Homeostasis Work?
Sleep-wake homeostasis is quite interesting, and understanding it does allow us to make better choices around our sleep hygiene practices. Adenosine is a molecule that forms part of ATP (Adenosine-Tri-Phosphate), and you may already know that ATP is the molecule that the body uses for energy, although it is involved in many other processes in the body. It makes sense that the energy molecule of the body plays a role in sleep, and it would seem intuitive that your body is sensing low energy and this is triggering sleepiness, but this isn’t the case. Your brain has receptors for adenosine, and throughout the day, adenosine binds to these receptors. When adenosine is bound, this serves to decrease wakefulness. This does cycle across the day, but in general, adenosine levels build up when you are awake, bind to the receptors in the brain and decrease arousal (and thus increase sleepiness). During sleep, the adenosine levels decrease and the receptors are cleared, leaving you to wake up feeling rested. As you can imagine, if you don’t get enough sleep, you are going to start the day with higher baseline levels of adenosine and have more receptors already occupied.
The longer you stay awake, adenosine levels continue to rise and more receptors get bound thus making you more and more tired. The only thing that can get these levels to drop back down is sleep. However, there are other things that we engage with that do interact with the system. Caffeine is a molecule that has a very similar shape to adenosine and can bind to those same adenosine receptors. However, while adenosine binding causes you to feel sleepy, caffeine doesn’t have this same effect as it doesn’t fit perfectly in the receptors (I always imagine this like a charging cable that looks like it should fit your device, but it doesn’t seem to actually charge your device when you plug it in, as they aren’t a perfect fit). Caffeine competes for the same receptors and thus, you can trick your sleep-wake cycle into thinking that you have less sleep drive built up than you do. Caffeine does have other properties that serve to increase wakefulness, but this mechanism is important to understand because caffeine does actually take quite a long time to break down in the body and thus it can interfere with your ability to get to sleep. Caffeine also only holds back the sleep drive for so long, and when sufficient caffeine has left the system, that built-up adenosine can hit you all at once and you can feel extremely tired. This is one reason some people get an afternoon slump when they drink coffee, they have built up a sleep debt by under-sleeping and then they use caffeine to trick the body into not feeling as tired, but once that caffeine wears off, the adenosine levels are at much higher levels and thus they feel all that sleep drive hit them at once. It is a vicious cycle to find yourself in, as most people will reach for a second coffee to overcome this afternoon slump, but this just pushes the problem out until tomorrow (and arguably makes it even worse tomorrow) as that second coffee likely causes you to struggle to get to sleep at night and to have poorer sleep in general, which means less adenosine is cleared during sleep. As you can imagine, this has implications for our basic sleep hygiene practices.
Now, there are other things that play into sleep regulation, but circadian rhythms and sleep-wake homeostasis are the big players and the ones that really influence our sleep hygiene practices. There is quite a lot in this section, and I know some of you are itching to just get stuck into the sleep hygiene practices now, but before we do that, I want to finally touch on the question of how much sleep we actually need, as that really wraps things up nicely and sets the stage for you to really build very robust sleep hygiene practices.
How Much Sleep Do We Need?
Before we discuss sleep hygiene practices, you need to know how much sleep you actually need to get. We have discussed the consequences of not getting enough sleep, what happens during sleep and what regulates your sleep, but we haven’t really touched on how much sleep you should be getting. However, the answer to this question is somewhat complicated, as sleep quantity is only really a proxy for what we want to know, which is whether or not the body was able to perform all the tasks it needed to perform while you sleep. We are actually more concerned about sleep quality than sleep quantity. If you can get 6 hours of incredibly high-quality sleep and feel rested and restored, that is obviously much better than getting 8 hours of poor-quality sleep which leaves you feeling tired and under-recovered.
Further complicating this is the fact that we all live different lives. The sleep needs of an athlete who trains 40+ hours per week are obviously going to be different than someone who sits at a desk all day. So any conversation about general sleep requirements is going to have to be modified to reflect your actual life situation. So we can’t just give a one size fits all answer to the question of how much sleep you need.
To really answer this question, we have to be clear about what we mean by sleep quality. Because if we know what high-quality sleep is, then we can better answer the question of how much sleep we need. High-quality sleep can be defined in many different ways, but the simple answer is that high-quality sleep is sleep that leaves you feeling restored and well-rested after it. Digging a little bit deeper, we can say that high-quality sleep is sleep that allows you to cycle through the various sleep blocks that your body needs and to adequately perform all of the various processes the body needs to perform while sleeping. So to measure high-quality sleep we can look to the polysomnography graphs we discussed earlier. High-quality sleep is going to have us cycle through 4-5 (and sometimes more) of these sleep blocks per night. This is still just a proxy for high-quality sleep, and you can have a good-looking graph on paper, but still feel under-slept. However, this is still a good starting point.
Now, considering that each of these sleep blocks is 80-120 minutes long and you need 4-5 of them, we can work out a rough estimate of sleep needs. Calculating this gives us a range of ~5.5 hours of sleep on the low end and 10 on the high end. So somewhere in the range of 6-10 hours is the standard recommendation for sleep. This is of course just a rough estimate, but for most people, sleeping somewhere in the range of 6-10 hours per day is likely going to cover their sleep needs. As most people are likely to fall into the average, rather than the extremes, 7-9 hours of sleep per night is a pretty solid recommendation that will cover the vast majority of people. If you are doing more than the average person cognitively or physically, the chances are that you are likely pushed closer to the higher end of sleep needs (i.e. 8-10 hours). There is a reason that hard-charging athletes try to get more than 8 hours of sleep per night.
The amount of time we need to sleep does vary across our life however, and this is generally reflected in changes in our sleep cycles (both quantity and duration). The following recommendations are the generic recommendations that are given for each age group:
- Newborn: 14-17 hours
- Infants: 12-15 hours
- Toddlers: 11-14 hours
- Preschoolers: 10-13 hours
- School-aged children: 9-11 hours
- Teenagers: 8-10 hours
- Adults: 7-9 hours
- Older Adults: 7-8 hours
As you can see, they do vary quite a bit, and in general, children need to sleep a lot more than adults. This is important to keep in mind, especially if you currently have or plan to have children in future.
In general, we tend to see that 7-9 hours of sleep per night is consistently associated with better outcomes. Some people may need more and some people may need less, but in general, if you can get 7-9 hours of sleep per night, you are likely to be in a good place. If you have a more (physically, mentally, and/or emotionally) demanding life, you may actually need more than this and you would probably be best served to get closer to the higher end of the recommendations (8-9 hours), but for most people, 7-9 hours is a good approximation of sleep needs. It should be noted that this is actual sleep, not just time in bed. If it takes you an hour to get to sleep, that doesn’t count towards the sleep amount, despite what many people seem to think. I generally advocate that people add an additional 30 minutes to their sleep requirements, to account for the time spent falling asleep. Ideally, you would also allocate 30-90 minutes before this to really start winding your day down and preparing for sleep (we will discuss this more in the sleep hygiene section and this also fits nicely with our recommendation to not eat food in the ~2 hours before sleep).
As a further warning, a lot of people will claim that they need less than the general 7-9 hours of sleep and while there certainly are outliers, most people aren’t outliers. Most people who claim they need less than 7-9 hours generally tend to sleep more on the weekends, they excessively rely on caffeine (or other stimulants) to get them through the day and very often they have the disrupted health markers that are seen in people that don’t sleep enough. So the likelihood that you need less than 7 hours is quite low, despite what you might see on social media.
Finally, when we suggest you need 7-9 hours of sleep, we generally mean that this is 7-9 hours of continuous sleep. You may be able to get similar benefits to 7-9 hours of sleep with something like 2 separate blocks of ~4 hours of sleep, but this is poorly studied. Splitting sleep up further than this likely isn’t ideal, and the research would seem to suggest that we ideally want to get those 7-9 hours as a fairly continuous block. Of course, very often sleep will be interrupted, and periodic wakings throughout sleep are relatively normal, but sleeping in smaller blocks of sleep doesn’t seem to confer the same benefits as sleeping in a fairly continuous block of time.
Naturally enough, your next question is likely “what about naps?”, as many people wonder where naps fit in with our sleep needs and how they also fit in with what we have discussed about circadian rhythms and sleep-wake homeostasis. In general, naps are to be avoided. They can be useful for reducing some of the sleep drive that is built up (either from a normal day or as a result of poor sleep acutely/chronically), but in most cases, they don’t allow for a full sleep block to occur (they would need to be 90-120 minutes long) and they usually just serve to make it more difficult to fall asleep later that day. You would generally be better served just trying to go to bed a little bit earlier, rather than having a nap. Of course, in the real world, sometimes they can’t be avoided and have to be part of the plan. For example, you may only be able to get 6 hours of sleep each night, but you can get a 2-hour nap in on top of this during the day. While not ideal, this may be a helpful strategy for ensuring you get the benefits of sleep.
Of course, most people don’t have the luxury of getting to nap during the day, but in some countries where the weather is very warm during the middle of the day, an afternoon nap is sometimes standard practice. However, this is generally a 90-120 minute nap and it is also accompanied by longer work days too (for example, in Spain they tend to have 2-3 hours in the middle of the day reserved for siesta (although not everyone does actually nap), but the work day is generally 9 am to 8 pm).
Shorter naps, less than 90 minutes are generally best avoided wherever possible, as they really only serve to reduce sleep drive, thus making it harder to get to sleep later in the day, without allowing you to get through a complete sleep block. Having said this, very short naps of 5-20 minutes may have benefits in mildly reducing sleep drive (thus allowing you to feel more awake) and also allowing you to shift into a more relaxed state (similar to how meditation works). Some people find that shorter naps are also good for helping them think through problems and be more creative.
Athletes or those with very demanding lifestyles may benefit from naps, as a kind of top-up to the 7-9 hours of sleep they should normally be getting. Many athletes do have a mid-morning/afternoon nap, and due to the high volumes of training they undergo, this doesn’t seem to disrupt their ability to get to sleep later that day. Much like how athletes may have to find inventive ways to get enough calories in, they may also have to find inventive ways to get enough sleep in.
To wrap this section up, the general recommendation is to get 7-9 hours of sleep per day. Ideally, try to avoid napping, unless you have a very demanding life and you are either having very short naps (<20 minutes) or are able to get a 90-120 minute long nap that doesn’t interfere with your ability to get high-quality sleep later that day. It should be noted that you have to be fairly consistent with this each day, and you can’t just catch up on sleep at the weekends. While catching up on sleep at the weekends may help you feel less tired, it doesn’t change the fact that you spent the rest of the week with all the negatives of a lack of sleep (such as dysregulated blood glucose, or the increased feelings of hunger or any extra calories consumed while sleep deprived, for example). I certainly wouldn’t advise against catching some extra sleep on the weekend if you have to, and if it doesn’t interfere with your ability to get to sleep on time later that day, but don’t think you can (fully) make up for poor sleep hygiene Monday to Friday by sleeping later or having a nap on the weekends.
Foundational Sleep Hygiene
Now, this is where we really put all the information we have learned into practice. While there are potentially millions of things you could do to improve your sleep, we want to focus on the highest-yield habits and set some foundational sleep habits in place. Some of these are quite intuitive, but that doesn’t mean they aren’t effective (or that people consistently do them). Sleep hygiene is the term that is often used to describe the behavioural and environmental practices that a person engages in to encourage good sleep. As individuals, this is the level that we have control over, although there are other things that can be done to improve sleep that would require a medical doctor and/or psychologist (and even when engaging with them, they will often advise starting with basic sleep hygiene practices as a first line intervention). So, what are these habits? Well, as discussed previously, there are quite literally millions of things you could potentially do to improve sleep, so what I have tried to do is to distil the essence of what various habits are actually working on, rather than focusing on specific habits. If you can understand the principle through which various habits work, then you can make better choices as to which habits you should be engaging with.
Track Your Sleep
When trying to improve your sleep, very often the first step is to just start actually tracking your current sleep. This doesn’t have to be excessive, and it can be as simple as writing down what time you get into bed and what time you wake up, and then maybe a rating of how well-rested you feel upon waking and throughout the day. However, with the availability of smartphones and smart wearables (notably watches and rings), it has never been easier to get a clearer picture of your sleep, at least quantitatively (i.e. how much sleep you got and what your sleep architecture looked like). These various devices aren’t perfect, but they do give you some information to work with.
Tracking your sleep is important because you want to be able to identify what you actually need to work on and then what is actually working and what isn’t. For example, by tracking your sleep for a week, you may notice that you feel well-rested earlier in the week, but by Thursday you are exhausted. You may also notice that you get 6 hours of sleep per night on weekdays, then 10 hours of sleep on Friday and Saturday nights and 8 hours on Sundays. Now you have very useful information in helping you solve your specific problems, and you can go about addressing them. In this case, you may simply just need to organise your schedule so that you can actually get ~8 hours of sleep on the weekdays.
Tracking doesn’t have to be excessive and I wouldn’t get too worried if your sleep tracking device says you get poor sleep and you otherwise feel great, as these devices aren’t perfect. But by tracking your sleep, you do gather a lot of information on how your habits are affecting you. This will really allow you to identify the highest yield habits for you. For example, I have had clients who noticed that wearing blue light blocking glasses before bed leads to a very dramatic increase in their sleep quality and ability to get to sleep, and I have also had clients that noticed absolutely no difference. Some people have noticed that the nights they leave the windows in the bedroom open increased their sleep quality, and others have noticed the opposite. Tracking your sleep allows you to better identify what works best for you and what things you need to really focus on if you want to get great sleep.
It should be noted that some people really do get too caught up in sleep tracking, and this can become somewhat pathological and actually hinder sleep. Sleep tracking devices should really only be considered a proxy for the stuff we care about with sleep. They aren’t perfect, and I simply wouldn’t be obsessed with the data they give you. If you find yourself getting excessively caught up in the data these devices give you, then you may need to take a step back from this habit and instead, just focus on engaging in the other sleep hygiene habits outlined below.
Have Consistent Sleep and Wake Times
This is usually one of the biggest return on investment habits that people consistently notice really improves their sleep quality and their ability to get to sleep. Having a consistent bedtime and wake time, even on the weekends, allows you to take full advantage of your circadian clock. If your body knows that you are consistently going to go to bed at 10 pm and wake up at 7 am, then it is going to do everything in its power to help you keep to this schedule. It will release the right signals at the right time to ensure you get sleepy coming up to 10 pm and wake up around 7 am. Your body likes consistency and regularity, especially when it comes to sleep. It is also important to keep the sleep and wake times consistent across the whole week, even on the weekends or days you don’t have work etc. You want your body to be able to follow a pattern and staying up late or sleeping in later on the weekends gives your body mixed signals. These mixed signals serve to make waking up and getting to sleep early harder the next few days
So if you want to improve your sleep, then setting a bedtime and wake time that you can fairly consistently stick to throughout the week is a really high-yield action item. Now, of course, setting a bedtime and wake time that doesn’t allow you to get your full 7-9 hours of sleep per night isn’t going to be ideal, so what we generally recommend that people do is to subtract 7.5-9.5 hours from their wake time and set that as your bedtime. Most people have a hard wake-up time, meaning they have to wake up at a certain time to get to work/school etc., so if you are to get your 7-9 hours you are going to need to at the very least be in bed 7-9 hours beforehand, and then we add on an extra ~30minutes to allow for you to actually fall asleep. If you know you need 8 hours of sleep, only allocating 8 hours to get that sleep done generally just doesn’t work. Most people don’t fall asleep straight away, and they take a few minutes to fall asleep. So you have to allocate time for this.
This is one of the highest yield habits, and unfortunately, it is one of the habits that usually gets tossed aside first. People will stay up late on their phones or watching screens and then simply not leave enough time to actually get their 7-9 hours of sleep. This then has the knock-on effect of making them more tired the next day, and it also means your circadian rhythm isn’t able to work with you to encourage sleep. Of course, if this happens occasionally, it isn’t a big deal, but if you go to sleep and wake up at different times each day, then getting consistent high-quality sleep can be quite difficult. Sometimes this is simply unavoidable, and for certain careers, shift work is just something that prevents consistent sleep and wake time being a possibility. However, there is a reason that shift work is considered by many experts to be a carcinogen (i.e. causes cancer) and we do know that shift work is associated with a variety of ill health effects. So it makes sense to avoid shift work if possible, and for people who can have consistent sleep and wake times, it makes sense to do that (within reason).
Include Wind Down Time
Continuing on from the previous habit, having a consistent wind-down time and protocol before bed can really improve sleep. The first step with this is actually setting time aside to engage in a wind-down practice before bed. As discussed above, we generally set aside ~30 minutes for getting to sleep right before bed, but beyond this, we also generally recommend that the last 1-2 hours before bed do actually have bedtime in mind too. You don’t need to be lying in bed for those 2 hours trying to get to sleep, but you can engage in activities in those ~2 hours before bed that increase the likelihood that you will get to sleep easily and that you will get deep, high-quality sleep.
The premise behind the wind-down time activities is simply to shift the body into more of a parasympathetic nervous system state (this is often called the “rest and digest” nervous system). We want to reduce excitation (sympathetic nervous system (fight or flight) activation) and start unwinding from the general stimulation of the waking day. There are many things we can do to really start unwinding and signalling to the body to start getting the sleep processes going, and you are going to have to play around with things to create your own unique systems. However, there are a few things that most people do find really helpful to schedule in this wind-down time period, and while this isn’t an exhaustive list, it should give you some ideas as to what you could do during that wind-down time period. I generally recommend that people pick a few that they feel they get benefits from and then try to do them in a somewhat consistent routine every night. This basically serves as a signal to your body/brain that it is time for sleep soon, and it is basically Pavlovian conditioning. Anyway, here are some ideas:
- Have a warm shower: While you do want a drop in body temperature to get to sleep, having a cold shower causes your body to subsequently heat itself up and as a result, this can interfere with sleep. So having a warm shower can signal to your body to try to cool down, which can then help you get to sleep more easily. 30-60 minutes before bed seems to work best.
- Deep, slow breathing: This can really help to relax the nervous system and help you get into a relaxed state before sleep. You would be surprised at how effective 5-10 minutes of deep slow breathing has on bringing down your overall arousal and levels of “awakeness”.
- Meditation: Similarly, to the last point on breathing, meditation can also be an incredibly valuable tool in helping you to wind down and get into a state that is more conducive to sleep.
- Stretching and/or manual therapy: Doing some light stretching and/or some form of manual therapy like foam rolling can help with relaxing the body and can help you to get to sleep a little bit easier.
- Journalling: Writing down your thoughts for the day and also potentially doing some planning for the next day can be incredibly helpful in reducing stress levels before bed and can really help you to clear your head and set you up for a good night’s sleep. You don’t have to do anything fancy for this, and you can literally just use a pen and paper and write down your thoughts, however, some people do find having some sort of prompts or a template to work with can be helpful (there are many specific journals that are sold online, and while some are better than others, the goal initially is to just get into a consistent practice with this).
- Reading: This is a classic pre-bed activity, and a lot of people find it incredibly helpful for getting them to sleep. Reading a physical book is preferred to reading something on your phone, as you can be kept awake by the light emitted from your phone and there is a greater chance of distraction with your phone versus a physical book.
- Aromatherapy: Some people find that they can improve their sleep by building aromatherapy into their pre-bed wind-down time. A lot of people swear by using scents such as lavender in the wind-down period to help get them to sleep. Some people use candles for this, but this does obviously increase the risk of fires if you fall asleep with a lit candle and thus other options like diffusers or aromatherapy sprays are preferred.
As I mentioned earlier, these are just ideas and this certainly isn’t an exhaustive list. In general, the wind-down period is all about forgetting the stress of the day and getting your body and mind into a state that is more conducive to high-quality sleep. Along with the kinds of activities that I have outlined, you also want to try to avoid activities that stress you out during this wind-down time. That means checking your emails, scrolling through social media, doing work, or watching TV are all the kinds of things you should avoid doing during the wind-down time.
Melatonin and cortisol secretion follow a circadian pattern, and are somewhat antagonistic to each other. Cortisol serves to wake you up, and melatonin serves to get you to sleep. While the two hormones aren’t actually antagonistic to each other, if cortisol is high, it will be difficult to get to sleep. This is why we generally want to try to reduce stress in the lead-up to sleep.
Manage Your Light Exposure
Managing your light exposure in the run-up to sleep is one of the highest-yield things you can do to improve your sleep. However, it can actually be quite hard to do in practice. As we discussed earlier, blue light interferes with melatonin synthesis and thus, when you are exposed to blue lights in the lead-up to sleep, you are likely going to find it harder to get to sleep. So, if you want to improve sleep, it is important to try to reduce your blue light exposure. This can be done relatively easily by reducing your screen viewing in the 1-2 hours before bed. Alternatively, you can install software that removes/reduces the blue wavelengths (f.lux is a commonly used one) or wear blue light blocking glasses when you are watching the screens later in the day. Of course, screens aren’t the only source of blue light, as the lights in your home are also likely emitting blue wavelengths. In the lead-up to sleep, you want to try to decrease the intensity of light exposure as well as those blue wavelengths and there are many ways to do this. Instead of using the overhead lights, you can use lamps that use blue light reduced bulbs or stuff like salt lamps. Fire or candles are also good sources of light in this time period, but again, having lit fires isn’t ideal if you fall asleep. You can also wear blue light blocking glasses if you can’t modify the actual lighting situation.
Ultimately, you want to reduce your blue light exposure in the 1-2 hours before bed, so melatonin levels can rise and facilitate you getting to sleep easily. However, it isn’t just the pre-sleep period that we want to manage our light exposure, we also want to try and get some quality light exposure early in the day. Remember, we want to entrain your circadian rhythm to the day cycle, so you do actually have to give it the signals that it is daytime. The best way to do this would be to get outside and get sunlight exposure early in the day (and throughout the day), and this does work even if there is cloud cover. If this is impractical, then you can use something like a SAD lamp (a lamp designed to help people with seasonal affective disorder), and having that on for a while in the morning as you get ready for work (or as you work if you do work from home) can be effective. Unfortunately, if the only sunlight you get exposed to is in the 30-second walk from your front door to your car door, that is unlikely to be a sufficient signal that is daytime and getting exposed to even harsh overhead office lighting isn’t going to solve this. Getting outside before work or at the very least during your lunch break will give you a better chance of getting the kind of light that you need to ensure your circadian rhythm is better aligned to the daytime, and thus will have you more likely to get to sleep at an appropriate time at night.
Ensure The Room Is Set Up For Sleep
You can do everything in the world to improve the likelihood of you getting to sleep more easily and increasing the likelihood of high-quality sleep, but if your sleep environment is not set up for sleep, you are always going to feel like you are swimming against the current. You can be incredibly drowsy and ready for sleep, but if your sleep environment doesn’t facilitate good sleep, you aren’t going to get good sleep. So, we ideally want to try to set up our sleep environment in a way that does actually lead to high-quality sleep.
To do this, the first step is generally to ensure that you are able to get your bedroom as dark as possible. Remember, light is a signal that is telling you that it is not time to be sleeping, so we want to remove that signal as much as possible. If you can set up your sleep environment so that it is so dark that you can’t even see your hand in front of your face, then that is likely the best option. This can be especially important in the summer months when the daylight hours are longer. You don’t want light keeping you up late or waking you up early, if you know that you simply need more hours of sleep to function well. Some people find sleep eye masks to be effective, but these can slip off and if your room is bright, this may lead you to wake up. Black-out blinds are the best option for ensuring your room is pitch black.
After this, we want to also ensure that the room is at the right temperature for sleep. For most people, this is going to mean the room should be a little bit cooler. There is some research into what the perfect temperature is, but realistically, we just want the room to be warm enough so that you aren’t waking up shivering during the night and cool enough that you aren’t sweating excessively throughout the night. This will take a bit of experimentation, and as most adults sleep in a room with their significant other, there will also likely be some compromise with the “perfect” temperature too. Some people go as far as getting specific mattresses that adjust the temperature so that they can really optimise their temperature and thus get quality sleep, but this isn’t necessary and you can get very far with just manipulating the temperature in the room, using an appropriate duvet for the season and modifying the amount of clothes you wear. Some people find success in having the house cool down as part of the general wind down period before sleep. When the house starts to cool down and your body temperature also cools down, you get a double whammy of the increased sleepiness due to your lower body temperature and the increased desire to get under your covers to stop you from getting too cold. Again, there will be some trial and error (and compromise) here. Women tend to run a little bit colder than men, especially if they are on hormonal contraceptives, and they tend to have smaller bodies, so there is a bit of a discordance between what men and women view as a cool environment. As a result, there will generally have to be some sort of compromise with the exact “optimal” temperature.
Similarly, if the environment is very loud, you are unlikely to get high-quality sleep. Some people (myself included) can sleep soundly even in very loud environments, but for the vast majority of people are going to notice loud environments lead to decreased sleep quality. This can be a tricky one to solve, especially if the noise is external (such as construction, traffic or you live near train tracks or an airport). However, you can try to ensure that what noise you can control is controlled, and then if that isn’t enough, you can use something like earplugs to try to encourage more restful sleep. Some people do find that having some sort of background ambient noise does actually help them to get to sleep and stay asleep. Stuff like air conditioning units, (de)humidifiers, “nature” soundtracks and devices that emit white noise are all stuff that some people find to be beneficial for their sleep quality, however, for others, this can prevent them from getting quality sleep.
Most people do find that having good-quality air circulating in the room is beneficial for sleep quality. Having the window open can help to ensure that sufficient oxygen is circulating in the room, and that excess carbon dioxide and water vapour aren’t building up. However, this obviously isn’t possible in some areas, and having the window open may actually reduce sleep quality (if noise levels are too loud, air pollution is high, or there is a high risk of someone trying to break into your home if the window is open). So this is something that you will have to modify to your exact situation, but having a well-oxygenated and ventilated room with circulating air can be very beneficial for improving sleep quality.
Finally, your actual sleeping equipment can either help or hinder your sleep. Ensuring your mattress is actually conducive to sleep for you is a major thing for improving sleep quality. Some people require a softer or firmer mattress to get quality sleep and obviously sleeping on a mattress that isn’t conducive to high-quality sleep for you is going to negatively impact your sleep quality. Further to this, ensuring that you are using an appropriate amount of pillows is important for high-quality sleep. Depending on your sleeping position, you may need more or less pillows. Depending on your body size, you may also need to adjust how many pillows you use, as bigger individuals may simply need more pillows to get good sleep. Some people find that fewer or even no pillows is their preferred pillow arrangement. You will likely have to play around with this until you find the right arrangement for you.
The blankets/duvet you use while sleeping can also affect your sleep quality. Having an extra warm blanket during the winter may be beneficial in keeping you at the right temperature, but it may be wholly inappropriate for use during the warmer summer months. So you will need to play around with this and see what works best for you. Generally, we do want to sleep a little bit on the cooler side, so if you frequently find yourself waking up sweating, then you are likely too warm while asleep and should either use a colder duvet or wear less clothes to bed. Conversely, some people find that their bedroom is too cold even with a warm duvet or they aren’t as capable of regulating their body temperature, and for these people, they may need to wear more clothes to bed, use an even warmer duvet or perhaps also add blankets to their bed set up. Some people do use electric blankets to help keep the bed a bit warmer, and this can help with sleep for those who do find that they get quite cold. Some people do also find that using weighted blankets can help them improve their sleep, although this isn’t always the case, and for some people, it actually makes their sleep quality worse.
Overall, you can actually modify your sleep environment quite a bit to help you to get better sleep. Some of the modifications are easy, and others are a bit more expensive or complicated, and a lot of them do require a bit of trial and error, but ultimately, you do spend about 1/3rd of your life in bed, so it makes sense to try and ensure your sleep environment it is set up for good sleep.
Reduce Your Use of Stimulants
While we have discussed a lot already, in reality, reducing the use of stimulants is likely the first step that anyone should do if they are having difficulties with sleep. Having a low stimulant intake is a fundamental sleep habit that most people choose to ignore. Obviously enough, taking stimulants close to the time you want to get to sleep isn’t going to be conducive to high-quality sleep. You can somewhat get around this by having a cut-off for stimulant use earlier in the day, but even this may not be enough if the stimulant takes a long time to be broken down in your body. For most people, caffeine is their stimulant of choice, although many students and “knowledge” workers are frequently turning to stronger stimulants like mixed amphetamines, methylphenidate and modafinil (among others). Some of these are designed to be longer acting, and thus they may still be at higher levels in your system when you are trying to sleep. All stimulant use is likely negatively impacting your sleep quality, and there is even research to show that relatively low intakes of caffeine consumed earlier in the day still leads to poorer sleep quality.
So if you are struggling with your sleep, it really does make a lot of sense to reduce your stimulant use, and unfortunately, this is usually the exact opposite of what people do. If you have had a poor night of sleep, most people turn to an extra strong cup of coffee in the morning to help them perk up a bit, and this caffeine intake is usually topped up a few times throughout the day. This can then lead to another night of poor sleep, and the process repeats. This doom loop of excess stimulant use in response to poor sleep causing further poor sleep is a difficult one to break, but it starts with reducing your stimulant (coffee) intake. You don’t have to go cold turkey on this, but reducing your stimulant use and having a cut-off for any stimulant us 8-12 hours before sleep is a good idea. This applies to everyone, not just those that are in this doom loop. Trying to keep your stimulant intake low and confined to the earlier part of the day is just good practice if you want to have high-quality sleep.
Even if you stay within the recommended ~400mg of caffeine per day intake level, depending on how you time your intake across the day, you can still experience significant sleep disturbances. As a result, if you are trying to improve your sleep, you should both reduce your total stimulant intake, and also try to confine it to the earlier portion of the day. Having a hard cut off point for stimulant use, 8-12 hours before sleep can be very helpful.
For most people, reducing the total stimulant intake (i.e. consuming less) and then also having a hard cut-off for stimulant use around ~8-12 hours before bed is all that is needed to really set things up to encourage good sleep. The tricky thing for most people is that they have become accustomed to relatively high intakes of caffeine, and don’t realise just how much or how close to bed they are consuming it. Most people are aware that coffee has caffeine in it, so they don’t find it as difficult to reduce their coffee drinking and keep it confined to the morning/early afternoon, but it is not uncommon for people to consume tea or caffeinated soft drinks later in the day, without realising how much caffeine they are still consuming. A cup of coffee has ~90mg of caffeine in it (although this varies depending on the size and brewing methods, and some coffees do actually have significantly more than this), a cup of tea has ~45mg of caffeine in it (although this also varies and some teas have significantly more than this), and a can of cola has 35-50mg of caffeine (depending on brand). I have seen people easily consuming 400mg of caffeine from tea and/or soft drinks late into the day (it wouldn’t be uncommon to see people having a cup of tea before bed in most parts of the British Isles), and not realise that this is likely partially responsible for their poor sleep and difficulties getting to sleep. When reducing your caffeine intake, you will need to audit your caffeine intake and really pay attention to where you are actually consuming caffeine (this very often surprises people, and then they have great difficulty in reducing their intake as they have many engrained habits around stuff like drinking tea late into the day).
Engage in Exercise
Exercise is one of those things that consistently is shown to improve sleep parameters. Getting some sort of exercise each day, even if it is something as simple as a walk can go a long way to improving your sleep. Exercising later in the evening and close to bedtime can interfere with your ability to get to sleep and may also alter your sleep quality, but outside of exercising in the ~2 hours before you intend to sleep, you really can’t go wrong with including exercise in your day if you want to improve your sleep.
Different types of exercise do have different effects on sleep, but I don’t think you even need to get this granular, as simply exercising in any form does seem to be effective for improving sleep. If you can get 30-90 minutes of exercise done during the day, then you should likely see improvements in your sleep.
While this subsection is quite short, exercise is actually one of those habits that gives you outsized rewards. Yes, you have to allocate time to exercise and you then actually have to do it, but if you do that, you are going to be rewarded with better sleep. You see both acute (i.e. same day) and long-term sleep improvements from including exercise in your day, so it makes sense to try to include exercise in your schedule.
As a bit of a side note to exercise, pain management is also fundamental to getting good sleep. If you can’t fall or stay asleep because you are in pain, then you are obviously not going to be getting high-quality sleep. Some of this pain can be due to issues that can be improved with exercise. Not all pain can be improved with exercise, but many body aches and pains can be improved with exercise. If you aren’t currently in pain, exercising is still a benefit here as it helps you build a more robust body and thus helps you to hedge against future pain disturbing your sleep. Of course, exercise can also be a source of pain too, so it is important to exercise in a safe and appropriate manner.
Optimise the Diet
As we discussed earlier in this article, sleep and the diet are very much linked, and we can ensure a higher likelihood of good sleep by following certain dietary principles. Following the general diet guidelines discussed in the fundamentals of nutrition article is a good starting point for this. For those of you who don’t want to have to read another article, here are some of the key points to keep in mind when trying to optimise the diet to help with your sleep:
- Eat a generally well-balanced, whole-food diet, ensuring that the majority of your diet is made up of a lot of nutrient-dense foods.
- Ensure you are eating a calorie-appropriate diet, so that calories aren’t too high or too low.
- Eat enough protein, as higher protein intakes do seem to lead to high-quality sleep.
- Try to eat 8-12 servings of fruits and vegetables per day, so that you are getting all the micronutrients you need to help support sleep.
- Don’t overly restrict any single macronutrient (i.e. don’t do low-carb, low fat or low-protein diets).
- Limit the consumption of foods that cause you any digestive issues or that just don’t seem to sit right with you.
There is no real secret to the diet, and it is something that is usually quite difficult to put into practice as you have to consistently look after it, but we do know that good diet patterns are associated with better sleep. Beyond the basic diet optimisation things we mentioned above and discuss more in-depth in the fundamentals of nutrition article, there are some things we can be a bit more specific with if we really want to ensure that the diet is supporting high-quality sleep.
The big player here is food timing. While food timing isn’t something you generally need to worry excessively about, we can manipulate the timing of our food intake to influence sleep. In general, leaving at least 2 hours between your last meal and bedtime results in better sleep. While some people feel that they need to eat something before bed to get a good night’s sleep, in most cases eating food close to bedtime is associated with poorer sleep. Now, of course, we want to ensure that we have consumed enough food both across the day and relatively close to bedtime to ensure that we aren’t waking up in the middle of the night absolutely ravenous. But in general, leaving at least ~2 hours between your last meal and bedtime will result in better sleep quality.
Similarly, tapering your water intake off as you get closer to bedtime is a good idea for most people. Some people find that if they drink water close to bedtime, they will awaken during the night needing to urinate. If this is you, then dialling back your water intake later in the day (but still ensuring that you are well hydrated) is likely a good idea.
Most people will also generally find that consuming some protein and carbohydrates in their evening meal tends to lead to better sleep. Some individuals do find that having a decent portion of their carbohydrates in their evening meal leads to better sleep, however, this isn’t always the case. Some people find that they need to have a more even spread of carbs across the day to optimise their energy levels and some even find that eating too many carbs at night leads to an easier time getting to sleep, but it actually leads to poorer quality sleep. So there is a bit of playing around with this stuff, and you will have to trial a few different options. However, as a baseline, most people tend to do well with a generally well-balanced mixed meal with sufficient protein, carbs, fats and fibre. So that would be the starting point for your evening meal, and then after that, you can look to play around with the exact ratios to try and figure out what works best for you.
Other than that, there aren’t many other dietary manipulations that tend to influence sleep and in reality, you will get the vast majority of your return on investment by virtue of just eating a generally well set up diet. There are significant barriers for some people in eating a well-balanced diet, and it certainly takes a bit of effort to consistently stick to a good diet, but if you can improve your diet, you generally also see sleep improve. As a nice bonus, once you improve your sleep, sticking to a healthy diet also becomes easier. This is unfortunately the opposite when your sleep is bad, and thus if you do struggle to sleep well, then you may find it more difficult to eat a healthy diet. But small changes do add up and it does become easier once you get a handle on either the sleep or diet side of things, as once you start improving one or the other, the other one also tends to improve.
Manage Your Bodyweight
Managing your body weight is a good idea if you want to improve your sleep. Generally speaking, individuals who are lighter tend to have better sleep. This is independent of body fat levels too, as bigger individuals who may be quite lean, but are heavier than the average person (such as strength athletes and bodybuilders), may also experience poor sleep as a result of their size. While higher body fat levels have a role to play, even high levels of muscle mass can be detrimental to high-quality sleep. Many heavier individuals find that they develop sleep issues such as sleep apnea (pauses in breathing or very shallow breathing while sleeping, and it often sounds like snoring/choking/gasping for air), and this prevents them from getting high-quality sleep. A large number of competitive bodybuilders (especially enhanced bodybuilders) require CPAP machines to help them overcome their sleep apnea and get good quality sleep. This is also a big issue for a large percentage of the population, however, they just haven’t been diagnosed. Many individuals may actually have sleep apnea and not realise it.
Sleep apnea makes it very difficult to get high-quality sleep and it is especially prevalent in populations who have a lot of mass (fat and/or muscle) on their stomach, chest, neck and upper back. As many individuals are carrying excess weight in these areas (50-70% of the population in most developed countries are overweight or obese), and thus the likelihood that these individuals are getting poor quality sleep is quite high and may be improved by losing weight. If you do need to lose body weight to improve your sleep, the ideal, best-case scenario is to lose body fat rather than muscle, but for some individuals, some muscle loss may be required to improve their sleep (i.e. some heavily muscled athletes may only be able to improve their sleep by losing muscle mass).
For most people, aiming to get to (and maintain) a healthy body weight will likely improve their sleep quality. This can be quite difficult, as poor sleep can make eating healthy hard, and this can then lead to excess fat storage over time. As a result, you get into a vicious cycle of having poor sleep, eating poorer and then continuing the cycle. But as discussed in the previous section, if you can get some momentum going with dietary improvements (and thus body weight improvements), you do also get into a positive feedback cycle where it becomes much easier over time. Little improvements really do add up here.
Manage Your Stress
While we have an entire article on the topic of stress management, it does just bear briefly repeating the sentiment of that article here. Sleep and stress are very intimately linked, and very often, the best sleep habits are actually just good stress management practices. So if you struggle with your sleep, and you have been diligently focusing on getting good sleep hygiene practices in place, and still aren’t seeing the results you want, then you may need to double down your stress management practices.
Sleep Conclusion
While there are a million things that you could possibly do to improve your sleep, these basic sleep hygiene habits generally seem to work for a large proportion of people and should serve as the baseline for improving your sleep. I know everyone wants to just be able to pop a pill or follow some super secret hack or trick to get better sleep, but it really just comes down to having consistently good basic sleep hygiene practices. Now you know why these practices work and why they are important, and hopefully, you have picked up some ideas as to how you can improve your own sleep by ensuring your basic sleep hygiene is in a good place.
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Paddy Farrell
Hey, I'm Paddy!
I am a coach who loves to help people master their health and fitness. I am a personal trainer, strength and conditioning coach, and I have a degree in Biochemistry and Biomolecular Science. I have been coaching people for over 10 years now.
When I grew up, you couldn't find great health and fitness information, and you still can't really. So my content aims to solve that!
I enjoy training in the gym, doing martial arts and hiking in the mountains (around Europe, mainly). I am also an avid reader of history, politics and science. When I am not in the mountains, exercising or reading, you will likely find me in a museum.
