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The Truth About Sleep And Memory

View our comprehensive guide on how lack of sleep (including sleep apnea issues) are linked to the different types of memory to find out the truth about sleep and memory.

03 Dec 2021 • 8 MIN Vincent Giampapa MD
sleep and memory

Getting a good night's sleep is essential for all systems of the body, from repairing muscle damage to helping you heal from an illness. Sleep is also vital for memory, and in fact, chronic lack of sleep or poor sleep hygiene can seriously affect your overall cognitive performance, especially creating memories. The two more relevant stages of sleep, slow-wave sleep (SWS) and rapid eye motion (REM) help integrate the information you learn each day into memories [1]. When you're learning a new task or going to school to learn new information, having plenty of sleep helps the body process the information and hold onto the memories.

Proper sleep, uninterrupted and with a long enough duration, allows your brain to process information and create memories. However, when your sleep is disrupted, such as in cases of sleep apnea, it's harder to form memories. Over time your cognitive ability and retaining new information suffers. This isn't an uncommon problem. In fact, over 1/3 of adults in developed nations get fewer than the seven to nine hours of sleep recommended by doctors [2].

In this article, we’ll discuss:

  • What happens in the brain when we sleep
  • How memory is created
  • What stages of sleep affect memory
  • How sleep apnea is linked to memory loss
  • The best sleep supplement to help you get more good quality sleep

We're also answering the question: How does sleep affect memory?

What Happens In The Brain When We Sleep?

According to the comprehensive sleep analysis, Why We Sleep by Matthew Walker, a preeminent neuroscientist and sleep expert, sleep affects both mental and physical aspects of our health and well-being [3]. Walker goes on to answer in-depth the theories of why sleep is vital for each memory process and how sleep affects memory.

Despite being a state of consciousness that takes up about a third of our life, sleep is still one of the great mysteries in life. Substantial research over the last several decades has attributed many positive functions to sleep – and some bizarre ones, such as a specific non-conscious state to help us with unfulfilled desires.

One of the primary functions of sleep is creating an environment for the formation of memories. New information like details about daily occurrences and deliberate learning, such as studying for a test, are stored in the brain's short-term memory center. The brain then creates memories as we sleep. Uninterrupted sleep allows this process to happen properly. If you don't get enough sleep, or if your SWS and REM sleep stages are interrupted, then your brain can't form the memories. Eventually, your cognitive performance suffers while you're awake.

Sleep also recharges our emotional brain circuits, allowing us to process stressful situations with a calm and steady head. The sleep state enriches a variety of brain functions, including those related to learning and memory. Sleep also regulates our hormone levels, including those responsible for appetite control and stress responses. Sleep deprivation negatively impacts our ability to ward off illness and disease. Chronic lack of sleep weakens the immune system and makes it more difficult for the body to repair damaged cells.

Understanding How Memory Is Created

To understand the effect of sleep on memory, it's necessary to understand memory itself and how memories are formed. There are three steps to making a memory:

  1. Acquisition is the introduction of new information into the brain that is derived from all types of sensory input.
  2. Consolidation is the process by which the acquired knowledge becomes a stable memory.
  3. Recall is the ability to consciously and unconsciously access information after it's been stored.

Research indicates that acquisition and recall only occur when we're awake while consolidation only occurs during sleep. As we sleep, the neural connection is strengthened, which cements the information into a memory. Research hasn't definitively discovered how this process happens, but studies indicate that the different stages of sleep and the associated brain wave patterns have something to do with the memory creation process.

Different stages of sleep are thought to create different types of memories.

What Stages of Sleep Affect Memory?

The first two stages of sleep are when the brain sorts through all of the day's information, from deliberate learning, such as studying for a test or practicing piano, to all the sensory input and information. The third and fourth stages of sleep are where the sorted information becomes a memory. Extra and unnecessary information is eliminated during slow-wave sleep and rapid eye movement, and essential information is transferred into the "memory banks."

Slow- Wave Sleep:

Slow-wave sleep is the third stage of sleep, characterized by slow brain waves, and is the point where information is processed and cataloged. The brain clears out beta-amyloid plaque during this stage – the same plaque found in dementia and Alzheimer's patients. This deep, restorative sleep stage plays a significant role in declarative memory, which is the fact-based knowledge of what we know [4]. It can be something as simple as what color shirt we wore yesterday to more complex, factual information.

SWS sleep lasts about 20 to 40 minutes and is essential for processing newly acquired information.

REM Sleep:

REM sleep is characterized by rapid eye motions and has shorter brain waves than SWS. It lasts from 10 to 60 minutes and processes new information, including information with emotions "attached" to it. REM sleep promotes declarative memory, making it essential for retaining knowledge that involves a lot of memorization. For example, in one study, people enrolled in an intensive language course were shown to have longer periods of REM sleep.

Scientists theorize that REM sleep is essential for the acquisition of learned material [5]. This stage of sleep creates the memories needed for school courses and memorization. Other studies indicate that REM sleep handles complex and emotionally charged information or creates more complex memories. If the information is simple and emotionally neutral, it is not processed during REM sleep.

REM sleep also plays a significant role in procedural memory, which is the memory of learning how to do something. It's usually some sort of activity, like riding a bike, playing an instrument, or learning a sport. While motor learning seems to be associated with the lighter levels of sleep, REM sleep is more closely related to the consolidation of procedural memory.

Sleep Apnea and Memory Loss

Extended rest interrupted by a condition called sleep apnea also affects memory. Obstructive Sleep Apnea (OSA) is a condition where breathing starts and stops during sleep. This is caused by the muscles in the upper airway collapsing and preventing normal breathing. When breathing stops, the person wakes up gasping for air. OSA may be a genetic condition, but people who have asthma or are severely obese can also suffer from the condition too.

It's estimated that over 936 million people worldwide suffer from sleep apnea, but it's a condition that can be easily diagnosed with a sleep study and treated with special equipment [6]. Sleep apnea is treated with a CPAP machine, which forces air into the lungs and allows the wearer to have a more restful night's sleep.

Because of the regular interruption of memory-creating sleep cycles, people with OSA struggle to recall details about their own lives and suffer from memory loss. Memory loss and difficulty with memory formation are also linked to depression, although the exact nature of the correlation isn't fully known.

One recent study shows that sleep apnea impairs the brain's capacity to consolidate or encode certain types of life memories, making it harder for the person to recall details about their past [7]. The study also showed people with OSA had significantly more overgeneral memories - 52.3% compared with 18.9% of the control group.

In addition to fewer specific memories, people with sleep apnea also have trouble with semantic memory. Semantic memories are about specific details such as the name of the first street you lived on, your childhood pet's name, or other facts and concepts from your personal history. However, episodic memory, which is the memory of events and episodes from your life, was preserved to the same degree as the control group.

These results indicate that OSA leads to cognitive impairment. However, conservative treatment and the use of a CPAP machine can help. The study also indicated that once patients were consistently using a CPAP, the overall quality of their sleep improved, and their ability to create semantic memories increased.

Supplements For Restorative Sleep

Sleep Supplement

Even without a medical condition like OSA that affects sleep, poor sleep can happen frequently. Students, travelers and business professionals working late nights often struggle to get adequate rest to accomplish more throughout the evenings. Unfortunately, the productivity that these populations desire by sacrificing sleep is actually lost because of their poor sleep habits.

Ensuring that you're getting enough sleep to have proper REM cycles can be tricky, but these sleep stages are vital to learning new information, preserving your memories, and avoiding cognitive decline. Even if you're in bed for seven to nine hours each night, you may not be getting the right kind of sleep.

If you're having trouble staying awake or remembering things, some supplements can help. REM Sleep is a sleep supplement that enables you to stay asleep and wake up feeling refreshed.† It contains 5HTP, vitamin B6, and GABA that help promote REM sleep. The right neural connections and chemicals need to be present for your brain to progress from one sleep stage to the next and properly catalog the information it's received throughout the day.

REM sleep supplements can help you naturally fall asleep fast and support all four stages of the sleep cycle.† The calming herbal ingredients can help soothe your mind, calm your racing thoughts, and prepare you for sleep. Specific nutrients are included to help your body lower its temperature, creating more restful sleep and making necessary repairs to your cells.†

Amino acids and hormones that promote longer REM sleep cycles allow your brain the necessary time it needs to catalog and form memories fully. With consistent use, you'll discover that you wake more refreshed and have better control over your emotions.†

REM Sleep is an all-natural sleep aid expertly formulated by physicians and nutritionists. It's made from non-habit-forming ingredients and allows you to reach your potential. Take the first step to healthy sleep habits and better cognitive function by trying the REM Sleep supplement and other liquid vitamins for adults from Healthycell.

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†This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.