Sleep and Memory: How Our Brains Consolidate Information During Rest

Lack of sleep directly affects cognition and memory recall. A growing body of research is painting a clearer picture of the link between sleep and memory.


Prioritizing sleep and getting at least six to eight hours each night can significantly affect your memory and problem-solving skills. Research indicates that retaining information and learning relies heavily on getting enough rest. Learning about the connection between sleep and memory will deepen your understanding of the process and might even inspire you to start improving your sleep habits tonight.

What Is the Connection Between Sleep and Memory?

Sleep and memory share a complicated relationship. When you get enough sleep, you can process new information better. In addition, going to sleep after learning something new helps you consolidate new information into memories, which allows you to store them in your brain and recall them more easily. These first three stages are called NREM (non-rapid eye movement) sleep.

Your sleep cycle has four specific stages. The first two are lighter stages of sleep, while the third state is deep, slow-wave sleep. During these NREM sleep stages, the brain begins sorting through memories and filtering out important ones while removing non-essential information. As deep NREM sleep transitions into REM sleep, these selected memories will become more ingrained in your memory.

Additionally, emotionally charged memories are processed during REM sleep, which can help you cope with difficult experiences as they arise. So, while slow-wave sleep sets the stage for memory recall, REM sleep stores these memories and "grows" the brain. One report calls this process "memory triage" and describes how the brain processes new information and decides what to retain and to forget.

Along with memory consolidation, as you sleep, the majority of dream activity also takes place during the REM stage. Within the brain lies the thalamus. This structure is responsible for regulating alertness, wakefulness and sleep. It also sends motor and sensory signals to the cerebral cortex. The thalamus is primarily inactive during NREM sleep, but as REM sleep begins, activity increases, and you begin to dream. As your brain consolidates memories while you sleep, this information also influences your dreams.

What Are the Effects of Sleep Deprivation on Brain Function and Memories?

Most people have experienced brain fog and exhaustion after a difficult night's sleep. Even just one night of less than six hours profoundly affects short-term memory. While everyone's experiences may differ, generally speaking, the longer you go without enough sleep, the more significant the impact on your brain. In addition, extreme sleep deprivation can drastically impair your judgment and make you behave as though you were intoxicated, even if you haven't had anything to drink.

Without enough sleep, you may have difficulty remembering things the following day. Problems with recall occur because your brain strengthens neural connections from the day before as you sleep, forming new memories. If you get up before you've rested enough, you won't receive as much REM sleep. You cycle through each stage several times before waking, with the last round of REM sleep being the longest. Without adequate sleep, your attention span wanes, your recall isn't as sharp and you may be more irritable.

While short-term sleep deprivation impacts short-term memory and retrieval, it doesn't impact deeper memories. Even when exhausted, you will likely remember essential details from your past, like the name of your childhood pet or the street on which you lived. While most people have sharp remote memories, a lack of sleep strongly affects adequate retrieval of recent information.

Insufficient sleep impacts the frontal lobe. This area plays a primary role in executive function (multitasking and making decisions) and memory retrieval. A 2022 study found that adults who reported sleeping three to six hours nightly performed much worse on cognitive tests than those who received enough sleep. These tasks also included an assessment of working memory (the ability to recall a small amount of new information). While it is possible to make up for a poor night's sleep by getting enough rest the next day, it becomes more difficult with age to bounce back from chronic sleep deprivation, especially since sleep quality tends to decrease as you get older, too.

Is There a Connection Between Sleep Disorders and Memory Loss?

Getting enough sleep is so critical to memory formation and consolidation that some sleep disorders are associated with memory loss. For example, there may be a link between insomnia, daytime cognitive impairment and reduced memory functioning. Narcolepsy, which is a condition known for excessive daytime sleepiness, may also cause memory lapses.

Another sleep disorder that may impact memory is sleep apnea. Sleep apnea is characterized by prolonged pauses in breathing while you sleep. As you rest, the muscles that support the soft tissue in your throat (such as your soft palate and tongue) relax, narrowing your airway and cutting off your ability to breathe. When this occurs, it causes you to wake up several times throughout the night, leading to daytime exhaustion, headaches and trouble focusing.

About 30 million people in the United States are affected by sleep apnea. Those with sleep apnea have tremendous difficulty getting a full night's rest. Irregular sleep patterns associated with this condition also put people at a greater risk of developing chronic depression. Depression causes people to have a more difficult time processing and consolidating memories. While current findings suggest a connection between sleep apnea and memory recall, more research is necessary to determine if there is a direct link or if sleep apnea and depression affect consolidation independently from one another.

Whether you're cramming for an exam or practicing a presentation, the best time to work through these tasks may be right before bedtime. Avoid "all-nighters," as these long study marathons come at the cost of a good night's sleep and tend to cause more harm than good. A quick review and at least six hours of rest will help you retain more information and wake up clear-headed and ready to take on any task that comes your way


Written by

Emily Mendez

Emily Mendez is a former therapist and mental health author. She is one of the leading voices in mental health. Emily's writing has appeared in eCounseling, SonderMind, and more. Emily is frequently interviewed by Healthline, Fatherly, INSIDER, Family Circle, and other national media for her advice and expert opinion on the latest mental health topics.

Copyright © Neybox Digital Ltd.