Sleep and Memory


Written by Rebecca Levi

Reviewed by Dr. Michael Breus

Our Editorial Process

Table of Contents

Sleep plays an important role in memory formation. Every day, we encounter a wealth of new information. During sleep, the brain has the opportunity to decide which recent memories are important enough to keep. In fact, experts believe that one of the key reasons we sleep is to form long-term memories.  

While getting a good night’s sleep can help strengthen memories, not getting enough sleep can impair your ability to recall information. Even though we know sleep is vital to memory consolidation, sleep is still elusive for many, especially if you have insomnia or another sleep disorder

We review how sleep affects memory and also offer tips for getting better memory-building sleep.  

What Is the Connection Between Sleep and Memory?

Current research suggests that the brain is very active during sleep, organizing and storing memories made throughout the day. 

Newly acquired memories are reactivated during sleep, which strengthens them and transforms them into more stable, long-term knowledge. There are three main mental processes involved with memory. 

  • Encoding: This is the first step in memory formation in which new information enters the brain. Memories can be fleeting at this point when they’re still new.
  • Consolidation: After the brain acquires a memory, it engages in a series of processes to strengthen and stabilize the memory. 
  • Retrieval: Retrieval is any time a person accesses a memory.  

While encoding and retrieval occur more frequently when a person is awake, sleep is thought to have a powerful role in memory consolidation, which promotes long-term memory.

Experts believe that memory consolidation may be effective during sleep because the brain doesn’t face as many external distractions as it does when awake. Moreover, the processing of information and experiences during sleep not only enhances each memory, but is linked to improvements in creativity, problem-solving abilities, and emotional stability. 

It’s also widely established that sleep is important both before and after learning. Getting enough sleep helps prepare the brain to learn the next day. And a good night’s sleep is important for reinforcing and organizing the information gathered during the previous day. 

Sleep Stages and Memory

The various stages of sleep may play distinct roles in memory consolidation. Throughout the night, you cycle through intervals of rapid eye movement (REM) and non-rapid eye movement (NREM) sleep. NREM sleep consists of three stages of increasingly deeper sleep. Experts believe that both REM and NREM sleep are involved in memory consolidation.

Research has demonstrated that REM sleep may be instrumental in processing non-declarative memories, which are those that help you carry out tasks automatically, without having to recall how to do so. Examples of non-declarative memories include motor skills, such as walking and writing, and procedural abilities, like driving a car or playing the piano. 

The processing of emotional events may also occur during REM sleep. Moreover, REM sleep seems to play a role in connecting memories. Experts believe this is why a good night’s sleep may help with tackling challenging problems or coming up with a new idea. 

Research has also indicated that slow-wave sleep—also known as stage 3 sleep or deep sleep—may be particularly helpful in the formation of declarative memories. Declarative memories are those related to facts and events that you can consciously recall.

It’s worth noting that recent research suggests that the relationship between sleep stages and specific types of memories may not be that straightforward. Some theories have shifted to considering a more significant role of NREM. Ultimately, more research is needed to fully understand how different sleep stages affect memory consolidation.

How Does Sleep Deprivation Impact Memory?

Sleep deprivation can impact not only a person’s daily functioning but also their ability to create memories and learn effectively. 

Adults should get between seven and nine hours of sleep each night. Quality of sleep is important too. If a person’s sleep is shortened or fragmented, they may not experience all the necessary stages of sleep. 

Not getting enough sleep can affect signaling in the hippocampus, a part of the brain involved in consolidating new memories, lowering your ability to retain information.

Research into the sleep patterns and memory functioning of older people may provide insight into the effects of sleep loss on memory. Memory tends to weaken as people get older. People also tend to experience poorer sleep quality and get less deep sleep as they age. Researchers theorize there may be a link between declining memory and declining sleep in older adults. 

Sleep Disorders and Memory Loss

Because sleep is so important for proper memory function, people with certain sleep disorders may experience issues with memory. Research has found that people with sleep apnea, insomnia, and narcolepsy often struggle with memory as a symptom of their condition. 

  • Obstructive Sleep Apnea: A person with obstructive sleep apnea experiences disrupted sleep as a result of breathing pauses throughout the night. Sleep apnea is known to affect memory and attention, which can lead to mistakes and accidents while working or at school. 
  • Insomnia: Insomnia can cause a person to get less deep, slow-wave sleep, which is associated with reduced memory consolidation. 
  • Narcolepsy: A person with narcolepsy feels the urge to fall asleep during the day, but they may also wake up many times in a night. If not treated, narcolepsy can affect various aspects of cognitive function, including memory and concentration. 

The good news is that research suggests that treating your sleep disorder may improve memory performance. It’s always a good idea to talk to your doctor if you are having trouble sleeping, especially if your lack of sleep is making daily tasks difficult.

Sleep Tips to Improve Memory 

Getting a good night’s sleep is critical for overall health, including remembering and learning. Following these sleep tips may help sharpen your recall and help you perform tasks or activities that rely on memory.

  • Sleep Before Learning: Make sure to get a solid night’s sleep before an important event or activity the next day, such as an exam or presentation. It’s common for students to pull an “all nighter” in hopes of cramming in a little extra learning, but doing so may actually impede the brain’s ability to remember facts.  
  • Sleep After Learning: The key to preserving and connecting information learned during the day is getting a good night’s sleep in the 24 hours that follow.
  • Exercise: Engaging in exercise helps many people sleep better at night and has also been shown potential to improve memory function. 

Understanding your natural chronotype may help you optimize your schedule and sleep habits.

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About The Author

Rebecca Levi

Staff Writer, Sleep Health

With a bachelor’s degree in anthropology from Indiana University Bloomington, Rebecca enjoys making accurate, up-to-date health information accessible to all readers. As a freelance writer and editor, she has covered everything from healthcare and experimental music to education. Rebecca lives in Tennessee, where she spends her free time reading, writing fiction, and making music.

  • POSITION: Side Sleeper
  • TEMPERATURE: Cold Sleeper
  • CHRONOTYPE: Dolphin

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