What Is REM Sleep and Why Is It Important for Your Brain?

You know those days when you wake up and you can remember some remnants of the dream that slipped past you? Somehow those days start extremely groggy while you’re still trying to make sense of the snippets you do end up remembering. Although, being honest, most of us do end up forgetting what we dreamt in the first 5 minutes. It’s easy to chalk up the sluggish feeling that accompanies you to just a busy morning or a bad night. 

The crux, however, doesn’t lie in the hours of sleep you get but in how efficiently your brain manages to move between the different sleep stages. One of the sleep stages at the center of this is the stage of REM sleep, i.e., rapid eye movement sleep. This is the stage that’s the most associated with vivid dreams, higher brain activity, emotional processing, and several forms of memory processing. Your consciousness might take a backseat while you’re sleeping, but that doesn’t mean that your brain and body just switch off during that period. Your brain actually sequentially moves from non-REM to REM and back to non-REM stages throughout the night. 

To get to the core of how sleep affects your energy, it might help to understand how interrupted or insufficient sleep can contribute to it even if you slept for the recommended 7-8 hours. REM and sleep in general can affect your memory, learning, emotional regulation, attention, and your overall cognitive performance, which is why this article might be a good read if you wish to know deeper about the ever-elusive REM sleep.

What is REM sleep?

The REM stands for rapid eye movement. This is when your brain is so active that the electrical activity of your brain from this stage can also resemble the activity of your brain when you are actually awake. So, technically, your brain seems wide awake during these stages. Your eyes then move rapidly under your eyelids, your breathing and heart rate change, and your muscles are temporarily blocked from moving. This is also the stage where inidivudals dream. 

What you have usually heard of sleep is that it’s supposed to be rejuvenating and restorative, and technically it is, but that is usually reserved for the non-REM deep sleep stages. REM happens to be a crucial period for your brain to process the information and experiences that you seemed to accumulate throughout the day while you were awake. This is exactly why researchers have been looking into REM sleep and brain health for years, particularly REM’s relationship with your memory and emotional processing. 

You do not continuously remain in the REM stage for the former or latter half of your night, but your brain alternatively moves through your sleep stages. Initially you have your non-REM sleep stages 1 and 2, then a deeper sleep stage 3, and then comes REM. Your brain repeats this pattern multiple times throughout the night.

Importance of REM sleep for Memory

One of the most talked about REM sleep benefits is how it helps your memory. However, it’s not that simple. Both REM and non-REM help in learning and memory consolidation. It doesn’t just help in storing them but also assists in sorting them, deciding what’s worth keeping and what gets tossed.

REM might be an important key in the storing and organization of emotional memories and the way the brain adds new memories to already stored information. Studies on REM sleep and memory have consistently found that emotional memory is heavily linked to the amount of REM an individual is able to obtain. People who get interrupted during this part of the night tend to do worse on memory tasks the next day compared to people whose REM wasn’t disturbed.

REM sleep and cognitive function

The brain engages in a surmountable amount of information processing when you’re sleeping, it’s one of the biggest benefits of REM sleep for the brain. Getting enough sleep helps an individual in learning, attention, memory formation, and even their performance the next day. 

REM has been assumed to help individuals integrate new information with the existing neural networks that their brain has. Researchers have hypothesized that the neural activity during REM can help with logical thinking and memory reorganization. This is why a problem that seemed impossible the night before seems manageable the next day. Your brain is working on the problem even while you’re sleeping and problem-solving. The brain uses this stage to basically rehearse and reorganize.

REM sleep and emotional health

The emotional systems and neural networks of the brain seem to remain active during the REM stages. Research has helped us understand that REM significantly helps in the overnight processing of emotional experiences of an individual and helps the brain in producing appropriate emotional responses. 

The relationship that REM sleep and mental health have is of utmost importance because sleep is one of the factors that largely gets interfered with in people who have mood or anxiety disorders. Studies have shown that people who have depression or PTSD often have abnormal sleeping patterns. Of course, these conditions and associations are much more nuanced than that, and an abnormal REM sleep cycle is not alone the causal factor. 

How REM Sleep Affects the Brain

During the REM stage, the brain activity significantly changes compared to the other stages. The cortex becomes increasingly active, and the regions involved in memory and emotional processing interact as well. However, there are significant differences between wakefulness and the levels of some neuromodulators.

One distinctive feature of REM is that the activity of noradrenergic signaling gets quite reduced. Research has proposed that this unique neurochemical environment can potentially allow the brain in processing experiences that are emotionally significant for the person but without the physiological stress that may accompany those emotional experiences if the person were awake. 

This is one of the assumptions that researchers have made to justify the activity of REM. However, research is still developing on this since sleep does remain to be somewhat of a black box in empirical research, and it is difficult to pin down one singular explanation. It would be inaccurate to claim that scientists have completely mapped every function of REM.

How Much REM Sleep Do You Need?

If you repeatedly wake throughout the night, snore heavily, experience breathing interruptions, or wake feeling exhausted despite sufficient time in bed, the issue may be sleep quality rather than simply REM duration.

This question pops up for tons of people. However, currently there is no universal number of hours or target that every adult should be targetting. REM does account for a good amount of your sleep, but the exact amount of REM each individual gets depends on their age, personal biology, sleep duration, and many other factors. 

The more practical goal each person can set for them is to try and get a consistent amount of sleep each night to achieve a healthy REM sleep pattern. Adults in general need about 7 to 9 hours of sleep in total, and keeping this amount consistent does seem to be the best bet. Messing with this amount can disrupt the normal distribution of sleep stages through the night. 

Why is REM sleep important?

Poor sleep quality, especially REM-deprived nights, tends to show up the next day as fatigue that coffee doesn’t really fix. Daytime sleepiness is one of the more obvious signs that something is a little off and wonky with the sleep architecture of a person. If you are dozing off during meetings or cannot stay alert during the day, you might want to look at how your brain and body are behaving at night when you are out cold.

Conditions like obstructive sleep apnea (OSA), insomnia, circadian rhythm disorders, narcolepsy, and some medications can affect the normal sleep architecture of a person and may require a professional evaluation.