Why Sleep is so Important for Learning


Everyone is different. That means everyone needs a different amount of sleep, everyone handles the lack of sleep differently, and everyone reacts differently to the various methods aimed at improving sleep or increasing alertness. Figure out what works for you, and as always, experiment with caution. This article is not meant to address genuine sleep disorders, such as insomnia, that require professional medical treatment. Please consult your doctor before using any medicines, chemicals, herbs, dietary supplements, or other treatments. This is an article about how sleep (or lack of sleep) affects the brain, and how to get better sleep. It is not health advice.

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Sleep matters.

Getting poor sleep or not enough sleep is associated with a wide variety of problems, ranging from anxiety to weight gain to car accidents. But, because this is an academic blog, we’ll stay focused on the impact sleep has on learning and school performance and what students and parents can do about it.

Sleep deprivation can result from insufficient sleep, poor-quality sleep, or both. Increasing the amount of time we sleep is largely about making sleep a priority and being strategic about what we’re doing in the evening. Improving sleep quality is primarily about understanding what causes poor sleep and addressing those issues.

But before we dive into this, please keep in mind that you don’t have to get perfect sleep every night in order to see benefits. There are many little ways to incrementally improve your sleep that, if done regularly, add up to big gains. Everything counts.

Academic Importance

Children and adolescents need more sleep (9-11 hours) than adults (7-8 hours).1 So don’t get mad at your teenager for sleeping in – that behavior is biologically driven. It seems likely that, because we have so much learning and development to do before we reach adulthood, we need more sleep.

Sleep is seriously important for academic success. Many studies have shown that sleep deprivation hurts grades. On average, A-students sleep 15 more minutes than B-students, B-students sleep 15 more minutes than C-students, and so on.2

Most students – along with the rest of us – aren’t getting enough sleep.3,4 Thankfully, some schools are pushing start-times back to help students get adequate sleep, but it will take far more than that to fix this problem.

What does sleep do for learning?

Sleep creates critical “space” in the spaced repetition program of memory-formation and comprehension.

Although you feel like you’re at rest while you sleep, your mind is unconsciously processing confusing information and difficult problems that you struggled with during the day in an effort to figure them out.6 It’s not uncommon to wake up in the morning with a better grasp of the previous day’s content or even wake up in the middle of the night with a creative insight about your work.6

Thus, inadequate sleep can hinder your process toward the first key milestone on the mastery path: understanding.

Sleep is also a critical part of memory formation. One thing sleep does “is erase trivial aspects of memories and simultaneously strengthen areas of importance.”6 In doing so, it consolidates what you’ve learned during the day into more coherent packages of knowledge. “During sleep, your brain also rehearses some of the tougher parts of whatever you are trying to learn – going over and over neural patterns to deepen and strengthen them.”6 Thus, without adequate sleep, you’re more likely to forget what you’ve just been studying.

How does being tired hurt students?

Aside from simply having a hard time staying awake in class, being tired hinders students in many ways.

Although IQ is problematic as a measure of intelligence, we can still use it as a proxy for cognitive ability, and the research is clear: sleep deprivation lowers IQ.2 And our performance on cognitively demanding tasks fluctuates enormously depending on how well rested we are. In one study, 6th graders deprived of one hour of sleep performed two grade levels below their performance on a full night’s sleep.2

Furthermore, merely shifting a full night’s sleep forward for a day or two and then back – say, by letting your child stay up late and sleep in on the weekends – is correlated with lower IQ scores.2 Regularity matters too.

Sleep-deprived individuals have reduced working memory.5 We normally have about four working memory slots with which to hold ideas in mind,6 but being tired reduces the amount of cognitive load we can carry. Our ability to access long-term memories and recall things we’ve learned is also diminished.5

Sleep deprivation also hinders executive function and all the skills associated with it. Tired people struggle with everything from emotional regulation to planning and decision-making.5 Sleep deprivation also reduces our cognitive flexibility, making us more rigid in our thinking and more likely to get stuck while trying to solve a problem.2 Impulse-control is also inhibited, which is why tired people are more likely to procrastinate.2

On the other hand, getting a good night of sleep makes just about everything easier. It even makes you more confident.

Key student abilities like paying attention in class and focusing on tests are also diminished by sleep deprivation. Much research shows that we have more difficulty paying attention and staying focused when we’re tired,5 so much so that sleep deprivation can produce ADHD-like symptoms in students without ADHD.7 And, of course, it exacerbates existing symptoms in those who do have ADHD.7 “If you’re short on sleep, you can’t concentrate. You’re likely to be sidetracked more often, and you’ll have particular trouble with long, repetitive tasks and anything that needs solid focus.”1

To sleep, or to study?

All this means that students will have some tough choices to make about how to use their time on school nights, especially when they’re doing last-minute cramming. Is it better to stay up late to get in some extra studying? Or is it better to study less and sleep more?

Learning expert Dr. Barbara Oakley has an answer:

“Going without sleep the night before an examination can mean that even if you are perfectly prepared, your mind is simply unable to function properly, so you do poorly on the test.” 6 Plus, studying while you’re tired isn’t particularly effective because “a sleep-deprived brain simply can’t make the usual connections you make during normal thinking processes.” 6

Why is being tired so harmful?

One reason for these challenges is that the prefrontal cortex, which is the primary seat of executive function and working memory, is particularly sensitive to exhaustion.5 Improving and increasing sleep is a simple and effective way to increase the strength of the prefrontal cortex.

Furthermore, sleep-deprived individuals are actually suffering from a buildup of waste products in the brain. Dr. Oakley explains:

“You may be surprised to learn that simply being awake creates toxic products in your brain. During sleep, your [brain] cells shrink, causing a striking increase in space between your cells. This is equivalent to turning on a faucet – it allows fluid to wash past and push the toxins out. This nightly housecleaning is part of what keeps your brain healthy. When you get too little sleep, the buildup of these toxic products is believed to explain why you can’t think very clearly.” 6

This is one reason why sleep is an essential part of brain health.

What gets in the way of good sleep?

Many things get in the way of a good night’s sleep, but luckily, most of them are under our control and relatively easy to address.


Humans evolved to be asleep when it was dark out and be awake when it was light out. With the exception of those keeping watch by campfire-light, we didn’t stay awake during the night because, well, it was dangerous. We evolved in Africa alongside big cats who were nocturnal hunters. It was better to stay quiet and hidden than walk around and risk becoming some leopard’s dinner.4

Thus, light and dark play a big role in the sleep patterns ingrained in human nature. When it gets dark, we’re supposed to feel tired. And, in general, we do. The trouble is, in the modern world, darkness is rare. Since the invention of electric light, the average person has been sleeping less and less.3 Our electric lights blaze long after the sun has gone down, and they trick us into feeling – unconsciously – like it’s still daytime.4 So we don’t get tired as early as we should, and we stay up later than we ought to. “This explains why even the most sleep-deprived cubicle worker tends to stay up late in the evening, without feeling particularly tired until it’s already too late to get a decent sleep.”1

Obviously, electric lights come with many benefits, and I’m not suggesting we do away with them, but we rarely consider their downsides, and we rarely make conscious choices about how to use them. I like to dim the lights in my apartment as bedtime approaches. Or sometimes I light candles and forgo electric lights entirely. This usually causes me to immediately feel more tired and realize that it is, in fact, time for bed.

And because the street lights outside my window can penetrate my curtains, I use thumbtacks and a thick blanket to make a black-out curtain each night. I sleep slightly better in a room that’s completely dark. Others use an eye mask.


The artificial light problem has only gotten worse in recent years as electric screens have become ubiquitous. Televisions, computer monitors, tablets, and smartphones all put out high-energy light from the blue end of the visible spectrum. This type of light is even more disruptive than electric light bulbs. Exposure to screens prior to bedtime disrupts the production of the sleep hormone melatonin, causing us to stay up later than we should and making it harder for us to enter into deep sleep when we finally do go to bed.4 So screens not only make you sleep for less time, but they also reduce the quality of your sleep.

Much of the cognitive processing we do during sleep seems to occur during REM sleep, which typically comes after a period of restful, deep sleep.1 Therefore, if we’re inhibited from entering into deep sleep by blue light, we’ll probably get less cognitive benefit from the time we spend sleeping, even if we’re getting adequate time.

For these reasons, sleep experts agree that reducing or eliminating screentime before bed is the #1 way to improve your sleep.4

The most radical solution to this is to practice what Brian Johnson calls a “digital sunset.” This means that when the sun goes down, electronics get turned off. Most of the time, though, this isn’t realistic. Both adults and students have to use their computers at night to get work done, and the prospect of giving up television, video games, texting, and social media in the evening is a tough pill for most to swallow. But you don’t have to go full digital sunset to see improvement.

There are programs and settings for computers, phones, and tablets that reduce their blue-light output, and this can be timed to automatically occur when the sun sets. My favorite free program is called f.luxThis is an easy, one-time setup that makes late-night screen use slightly less disruptive, so it’s a quick way to make an incremental improvement to your sleep.

You can also buy a physical screen filter that goes over your computer monitor and blocks blue light, or, as I have done, this rad pair of orange glasses:

These glasses fully block blue light and dramatically reduce the intensity of regular electric lights. They’re weird, and I wouldn’t call them “cool,” but they do work. If you have to stay up working on a computer, but you also need to prepare your brain for bed, these are the best thing I’ve found. They make me fall asleep faster and sleep better, and I notice the difference the next day. Oh, and they only cost $10.

Tech Addiction

If screentime is the #1 cause of poor sleep, then we’re not getting through this article without discussing tech addiction.

We all have to come to grips with the fact that, although our technology is wonderful and useful, it’s also got us hooked. The designers of apps and websites and games get paid to keep us glued to our screens.8 We’re not about to give up our technology – nor should we – so we’d better figure out how to have a healthier relationship with it. And that begins at home.

While young children will need you to set boundaries for screentime, older children and teens might be strongly resistant to imposed boundaries. There are two approaches here, which are not mutually exclusive: affirming family values around screentime and leading by example.

You could decide that, as a family, you’re going to establish set times when everyone’s electronics go away. Then it’s not about the child’s behavior, it’s about what’s best for the family as a whole. And this can be presented as something that’s really about your issues with electronics, tech addiction, and sleep deprivation, and your desire for quality family time. This approach will be met with less resistance than a rule imposed by parents to fix the child’s problem with tech.

And let’s be honest, adults are just as likely to have a problem with tech addiction as children. Just because you’re using your electronics for work and email rather than games and Instagram doesn’t mean you’re not using them too much. Your children need to see you lead by example and put your tech away. Spend more time in airplane mode, read more books, play more board games. If you want your kids to reduce their screentime, they’ll have to see you reduce your screentime first.

And lastly, if you keep your phone on your nightstand, that’s creating a temptation to look at a screen right before falling asleep. Instead, keep your phone plugged in on the other side of the room, not right next to your bed. You may still be tempted to use it, but at least you’ll have The 20-Second Rule working in your favor. (For more strategies on how to stop using your phone in bed, read this.)


Although caffeine is often used because people are sleep deprived, it can itself be a cause of sleep deprivation.

Caffeine is the most commonly used “solution” to being tired. I’m not here to tell you to never use caffeine. As someone who drinks coffee daily, that would be hypocritical of me. Instead, I want to suggest that you establish a caffeine cut-off point – ideally at noon or mid-afternoon at the latest.4

The reason for this cut-off is that caffeine has a half-life in the body of about five hours, depending on the metabolism and sensitivity of the person in question.4 So if you consume caffeine in the late afternoon or evening, plenty of it will still be in your system at bedtime. It will either keep you awake or, if you do fall asleep at the normal time, inhibit your access to deep sleep.4


I, for one, am prone to staying awake far longer than I should if there is something exciting going on. Often this excitement is self-imposed: television or games or a good book. I do much better if I make a point of winding down prior to bedtime with some calm activities like meditation and stretching. I also use chill music to unwind in the evening, and this helps pave the way for sleepy-time. My favorite source of relaxing music is this lofi YouTube channel.

People often make the mistake of checking the news, social media, or their email right before bed, and there’s a problem with this beyond the effects of looking at a screen. Checking email might send your brain back into work mode, and checking social media or the news might get you excited or upset. Think of your brain as a snowglobe. As bedtime approaches, the snow is settling down as you relax and unwind. Unless you want to have a hard time falling asleep, don’t shake the snowglobe.

Anxiety and Excessive Thinking

Some people are kept awake by their thoughts and anxiety.

One simple tactic that has been shown to help with this is “gratitude journaling.”9 This is the practice of writing down a few things that you’re grateful for. These could be big things or small things, things that happened today or things that happened in the distant past. Perhaps forcing your mind to think about what’s going well in your life gets you out of the downward spiral of negative thinking. Perhaps reliving positive events in your mind has a calming effect.

Whatever the reason, the research shows that reflecting on what you’re grateful for right before bed or as you lie down results in better sleep.9 Gratitude journaling also has other benefits, increased happiness being the most principal among them. Click here to learn more about how it works.

Another research-backed method is mindfulness meditation. People who meditate in the morning have an easier time falling asleep at night,4 and this may very well be because meditation reduces anxiety.10

Lastly, try planning your day out the night before. If your mind is mulling over tomorrow’s tasks, you’ll find it hard to get to sleep. But if you write those tasks down and make a concrete plan, you’ll have an easier time letting them go and relaxing. Plus, planning your day out the night before will make you happier.


We sleep more poorly if we’re overheated, while a cool room improves sleep.4 I usually keep the window of my room open for a few hours before bedtime to cool the room prior to applying my black-out curtain.

Poor Breathing

Sleep apnea – difficulty breathing during sleep – causes impaired sleep and can produce the effects of sleep deprivation even if you’re technically in bed sleeping for 8 hours.11 Because you’re not breathing well, you’re not sleeping well. So this is an issue that needs to be addressed. It’s worth consulting your doctor and finding a specialist. If you’ve already “tried everything” to address sleep apnea to no avail, consider trying the methods laid out in this book: The Oxygen Advantage.

One method from that book that has made a huge difference for me is taping my mouth shut to ensure that I breathe through my nose. It sounds crazy, but it really works.

Eating too Close to Bedtime

Another surprising thing I learned recently is that eating too close to bedtime impairs your sleep. This is because of the brain flush Dr. Oakley described earlier. It turns out that the process of cleaning out your brain at night requires a lot of blood. If you’ve just had a big meal, too much of your blood will be devoted to digestion, so you won’t get a good brain flush. (For more details, read this.)

Lack of Exercise or Exercise Late at Night

Lack of physical exercise during the day and exercise near bedtime can both make it harder to go to sleep. Research shows that the best time to exercise to improve your sleep is in the morning.12


I mentioned earlier that “sleep shift” – changing the time you go to bed and wake up day-to-day – can cause the same effects as sleep deprivation. In general, the more consistent you are with your sleep patterns, the better your sleep will be. This means, as much as possible, going to bed and getting up at the same time every day.3 You can also establish bedtime routines that you do at the same time every night in order to wind down. The more sleep is governed by ritual, the better it will go.4

Making up for Lost Zzzzzzs

Sleep Debt

Have you ever noticed how you still do pretty well after one night of insufficient sleep, but by the second or third day in a row of not sleeping enough, you’re really struggling? This is the result of sleep debt. “People who miss a few hours every night build up a sleep debt – that is, they need to sleep longer to put their brain back on an even keel.”1

Shorting yourself on sleep night after night creates a cumulative negative effect that can be as bad as the effects of pulling an all-nighter or two. Matthew MacDonald, author of Your Brain: The Missing Manual explains:

“In fact, studies show that regularly missing one or two hours of sleep a night can quickly add up to the same problems that are typically seen after one or two nights of total sleep deprivation. Even worse, people who are short-changing their sleep know they’re tired, but don’t realize that their sleep debt is adding up to some serious trouble. Shambling about in an all-too-familiar fog, they have no idea that their performance is at rock bottom levels.” 1

If you have accumulated a sleep debt, you’ll want to repay it as soon as possible,3 but this can prove to be challenging. You can’t make up for any significant amount of sleep deprivation in one night,13 which is why one of our exam-week recommendations is to prioritize sleep for several days leading up to a big test.

In fact, it can take months to fully recover from chronic sleep deprivation.13 But remember, perfection is not required, and perfectionism isn’t helpful. Any step we take to improve our sleep or repay some of our sleep debt is a good choice. And, sorry, but you can’t declare sleep bankruptcy.


When you don’t get enough sleep, you can make up for lost time with a quick nap. And naps don’t just feel good, they also provide real cognitive benefits. Research shows that naps can “improve the brain’s attention and performance, … stave off mental burnout, and keep your brain sharp for longer periods of time.”1

However, “the secret to getting a good nap is to break it off before you enter the deepest part of your sleep cycle.”1 I find that anything longer than 30 minutes leaves me feeling groggy. So set an alarm!

A possible trade-off is that longer naps come with additional memory-consolidation benefits. Neuropsychologists at Saarland University found that a nap of 45-60 minutes “‘produces a five-fold improvement in information retrieval from memory.’”14 Shorter naps may also produce a similar benefit, but I couldn’t find any research on that.

Naps can also be a way to tap into the power of “diffuse-mode” thinking, leading to improved understanding of difficult concepts and increased creativity.6

Waking Up

Waking up is a whole other challenge, and waking up well can pave the way for a good day and a good night’s sleep. Click here to read about my morning routine.

Make Sleep a Priority

If you take only one thing away from this article, please make it this. Sleep is critical for learning, executive function, and mental health. We need to make sleep a priority in our homes and in our culture. Sleep is not a luxury; it’s essential.4

Now, if you’ll excuse me, it’s nap time.

1 MacDonald, Matthew. Your Brain: The Missing Manual. O’Reilly Media, 2008.

2 Bronson, Po and Ashley Merryman. NurtureShock: New Thinking About Children. Twelve, 2011.

3 Maas, Dr. James B. Power Sleep: The Revolutionary Program That Prepares Your Mind for Peak Performance. Villard, 1998.

4 Stevenson, Shawn. Sleep Smarter: 21 Essential Strategies to Sleep Your Way to A Better Body, Better Health, and Bigger Success. Rodale Books, 2016.

5 Alhola, Paula and Päivi Polo-Kantola. “Sleep deprivation: Impact on cognitive performance.” Neuropsychiatr Dis Treat. 2007 Oct; 3(5): 553–567.

6 Oakley, Barbara. A Mind for Numbers: How to Excel at Math and Science (Even if you Flunked Algebra). Penguin, 2014.

7 Michael J Breus Ph.D. “ADHD or Sleep Disorder: Are We Getting It Wrong?” Psychology Today. May 1, 2013.

8 Alter, Adam. Irresistible: The Rise of Addictive Technology and the Business of Keeping Us Hooked. Penguin Press, 2017.

9 Emmons, Robert. Thanks!: How Practicing Gratitude Can Make You Happier. Mariner Books, 2008.

10 Lake, James, MD. “Meditation Reduces Anxiety.” Psychology Today. Feb 26, 2017.

11 McKeown, Patrick. The Oxygen Advantage: Simple, Scientifically Proven Breathing Techniques to Help You Become Healthier, Slimmer, Faster, and Fitter. William Morrow, 2015.

12 Fairbrother, Kimberly, et al. “Effects of exercise timing on sleep architecture and nocturnal blood pressure in prehypertensives.” Vasc Health Risk Manag. 2014; 10: 691–698.

13 Webster, Molly. “Can You Catch Up on Lost Sleep?” Scientific American. May 6, 2008

14 Axel Mecklinger quoted in “Neuropsychology: Power naps produce a significant improvement in memory performance.” ScienceDaily. March 20, 2015.

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