​​​​How Does Sleep Affect Learning and Memory?

By Nadia Gonnermann

Sleep often feels like wasted time, especially when exams and deadlines are coming up. But sleep isn’t just “rest time”, and your brain is anything but inactive. In fact, sleep plays a huge part in how well you learn and remember information. For teenagers whose brains are still developing, sleep isn’t just helpful - it’s essential.

In this article, we’ll look at how learning changes the brain, how sleep supports memory, and why getting enough sleep is essential for learning and memory.

Image source: Canva.

How Does Learning Affect The Brain?

Every time you learn something new, the brain physically changes. The brain is made up of billions of nerve cells called neurons. These neurons communicate across connections called synapses, using chemical signals (neurotransmitters). The more you use certain connections, the stronger they become. The repetition helps stabilise these connections and turn new information into something that can be remembered and used again.

However, learning doesn’t finish when you stop studying. During the day, your brain takes in huge amounts of information, but a lot of it is fragile and easy to forget. A brain region called the hippocampus helps to organise new information and decide what’s worth keeping. However, before memories are stored long-term, they need further processing and this happens most effectively during sleep.

How Does Sleep Work?

Sleep isn’t just one long, quiet state. Throughout the night, your brain cycles through different stages, which are grouped into REM (Rapid Eye Movement) and non-REM sleep (comprising N1, N2, and N3 stages).

 The Sleep Cycle: During sleep, the brain cycles through different stages: N1 and N2 (light sleep), N3 (deep sleep), and REM sleep (when most vivid dreaming happens). Moving through all of these stages is important for learning and memory, as each one helps the brain process, organise, and store information learned during the day. Created by the author. 

Non-REM sleep involves deep sleep and happens more at the start of the night. During this stage, the brain replays activity from the day and helps move information into long-term memory. This process is especially important for facts, vocabulary, and skills.

REM sleep is more common later in the night and is when most dreaming happens. Research suggests this stage plays a bigger role in emotional processing, creativity, and linking new ideas with what you already know. This can help you to see patterns you might not notice while awake.

Together, REM and non-REM sleep allow the brain to strengthen useful memories and weaken connections that aren’t needed. This overnight “maintenance” prevents the brain from becoming overloaded and keeps it flexible to learn new things the next day.

How Does a Lack of Sleep Affect Learning and Memory?

When you don’t get enough sleep, the effects aren’t just about feeling tired. Sleep loss affects memory at three key stages:

·  Before learning

Scientists have looked across decades of studies and found that a lack of sleep before trying to learn something is especially harmful for memory. When the brain is sleep-deprived, it struggles to properly record new information in the first place, meaning less of what you study actually gets stored.

·  After learning

Sleep is also essential after learning, because this is when the brain turns information into long-term memory. With poor sleep, the memories remain fragile and are more likely to fade. This is particularly important for complex ideas and problem-solving.

·  During recall.

Even if something was learned earlier, tiredness can make it harder to remember. Students who don’t get enough sleep often feel more distracted and less motivated, which can harm performance in exams. Some scientists call this a temporary “block”; the information may still be stored, but the tired brain struggles to access it.

A lack of sleep affects learning at every stage. This explains why pulling an all-nighter before an exam often backfires. A tired brain simply isn’t set up to learn effectively.

Even a “Bit Less” Sleep Matters

Sleep loss doesn’t need to be extreme to cause problems. Research shows that regularly getting 3-6.5 hours of sleep instead of the recommended 7-11 hours makes it harder to form memories. In some cases, the impact looks similar to missing a whole night of sleep.  

This partial sleep loss is common in teenagers. Teenagers experience a shift in their body clock, meaning they feel alert later at night and find it harder to wake up early. When this is combined with early school start times, homework, and evening screen use, many students don’t get enough sleep. In fact, this affects around 75% of teenagers.

Research shows this really does affect learning. Teenagers who slept 5 hours per night for 5 days (a typical school week for some) showed clear problems with memory formation that didn’t disappear even after several nights of recovery sleep. In other words, catching up at the weekend doesn’t undo the effects of poor sleep during the week.

Feeling tired can become normal, even though the brain isn’t getting what it needs to learn at its best.

What Can You Do to Improve Learning and Memory?

So, what can you do to improve learning and memory? Here are 3 simple ways to make a real difference.

Image source Natural Bio Health.

1.  Sleep within a few hours after studying.

Research shows that going to sleep within a few hours after studying gives your brain the best chance to strengthen what you’ve learned. You don’t need to fall asleep immediately, but avoid late-night revision and all-nighters because they interfere with this process.

2.  Protect the quality of your sleep.

It’s not just how long you sleep that matters, but how well you sleep. Late-night screen use and caffeine reduce the amount of deep and REM sleep you get. Limiting screens for at least an hour before bed and avoiding stimulants in the evening helps your brain reach the sleep stages it needs.

3.  Treat sleep as part of revision, not a break from it.

Sleep isn’t time away from studying. It’s when what you’ve learned becomes easier to remember. By protecting your sleep, the hours you spend working become more effective.

Sleep isn’t a luxury - it’s a core part of how learning works. Without it, much of the effort put in during the day is wasted. Treat sleeping as part of your study plan, not the first thing to sacrifice.

References:

Main paper: Crowley, R., Alderman, E., Javadi, A.H. and Tamminen, J., 2024. A systematic and meta-analytic review of the impact of sleep restriction on memory formation. Neuroscience & Biobehavioral Reviews, 167, p.105929. DOI: 10.1016/j.neubiorev.2024.105929.

Bartel, K., Scheeren, R. and Gradisar, M., 2019. Altering adolescents’ pre-bedtime phone use to achieve better sleep health. Health communication, 34(4), pp.456-462. DOI: 10.1080/10410236.2017.1422099.

Cousins, J.N., Sasmita, K. and Chee, M.W., 2018. Memory encoding is impaired after multiple nights of partial sleep restriction. Journal of sleep research, 27(1), pp.138-145. DOI: 10.1111/jsr.12578.

Crowley, R., Alderman, E., Javadi, A.H. and Tamminen, J., 2024. A systematic and meta-analytic review of the impact of sleep restriction on memory formation. Neuroscience & Biobehavioral Reviews, 167, p.105929. DOI: 10.1016/j.neubiorev.2024.105929.

Newbury, C.R., Crowley, R., Rastle, K. and Tamminen, J., 2021. Sleep deprivation and memory: Meta-analytic reviews of studies on sleep deprivation before and after learning. Psychological bulletin, 147(11), p.1215. DOI: 10.1037/bul0000348.

Whitney, P., Kurinec, C.A. and Hinson, J.M., 2023. Temporary amnesia from sleep loss: A framework for understanding consequences of sleep deprivation. Frontiers in Neuroscience, 17, p.1134757. DOI: 10.3389/fnins.2023.1134757.