You may have experienced that on some nights you dream much more than on others. You may have wondered why this occurs. This is because of something called REM rebound.
So, what is REM rebound? In this article, we’ll discuss everything that is to know about REM rebound and what causes this. So, read on…
So, what is REM rebound? Well, before we go on to understanding REM rebound, let’s understand the basis of REM sleep.
The sleep cycle essentially comprises 4 stages—the first 3 stages are known as the NREM (non-REM) stage sleep, while the 4th and last stage is the REM (rapid eye movement) sleep.
The NRM sleep includes 3 stages:
- N1: This is a very light sleeping stage, where you’re just beginning to fall asleep and can easily be woken up.
- N2: In this stage, the body temperature drops, the heart rate slows down and your eyes stop moving.
- N3: This is the deep sleep stage, where the body repairs the tissues, muscles and immune function.
These 3 NREM stages of sleep help you to sleep deeply before the REM stage starts. After you fall asleep, your body enters the REM stage after around 70 to 90 minutes, where the brain becomes very active.
The REM stage is associated with dreaming and it is the stage where the brain solves your problems, stores memories and also helps to enhance your mood.
Why Is REM Sleep Important?
There is plenty of research that supports the view that REM sleep, as well as dreaming, is very important and helps to modify our emotional responses while reframing any negative experiences.
It also helps sleep homeostasis and hormonal balance. To ensure that the regular sleep patterns are restored, which is very important for our general health and mental well-being, periods of intense dreaming are required to enable the sleep cycles to restore and reset.
What Is REM Rebound?
Typically, a night sleep cycle comprises around 4 to 5 periods of REM sleep that increase in their duration during the night and when we consider a typical 8-hour sleep cycle, around 90 minutes or more is spent in REM sleep, most of which occurs towards the morning hours.
If the body becomes deprived of REM sleep, your body moves to the REM sleep stage as soon as you fall asleep instead of going through the gradually deepening NREM sleep that begins your sleep at night.
When the body makes up for the sleep it has missed after a period of REM deprivation, this sleep stage increase is known as REM rebound. REM rebound sleep is marked by more REM sleep all through the night as compared to the regular length and frequency of sleep during the normal REM sleep.
While REM sleep constitutes around 20% of the sleep stages, in the case of REM rebound sleep, there is a 7% increase in REM sleep.
Typically, the REM rebound stage of sleep involves a shift in the regular sleep cycle and intense dreaming. Once the REM sleep deficit is made up by the body, the sleep cycle goes back to normal.
However, it can take several days or weeks for the sleep cycle to get back to normal, depending on how long and how much the sleep cycle has been impacted.
Why Does REM Rebound Occur?
The simple explanation for the cause of REM rebound is deprivation of REM sleep. When you don’t sleep enough and miss hours of sleep, the brain does not get the number of sleep cycles it requires, which includes REM sleep.
When this occurs continuously, the body gets less and less REM sleep and over time, the body begins to build up REM sleep debt.
When you go to sleep, the body attempts to make up for this REM sleep deprivation by making the REM stage longer, as well as more recurrent.
REM rebound is characterized by the first REM period, which is experienced as soon as you fall asleep instead of after the normal 70 to 90 minutes.
And, every REM cycle that you experience after this is much longer than it is normal and during these REM cycles, the dreams that you get are intense and vivid.
In fact, sometimes the dreams are so intense that you wake up suddenly and can even experience sleep paralysis.
REM sleep can be reduced by sleep deprivation and other factors such as if you take antidepressants or SSRIs (selective serotonin reuptake inhibitors) and all these also increase REM latency.
Some of the other factors that cause REM rebound include drinking alcohol, substance abuse and the use of CPAP treatment for sleep apnea.
Effect of Alcohol on REM Rebound
Consuming alcohol can shorten the REM cycles especially during the early sleep cycles. As the alcohol is metabolized by the body, there may be withdrawal symptoms such as disruption of sleep and waking up frequently that can cause REM rebound, REM rebound, insomnia and nightmares.
Effect of Substance Abuse on REM Rebound
REM rebound is commonly seen when a person taking any substance such as cannabis, antidepressants like paroxetine, citalopram, etc. and benzodiazepines, which suppress REM sleep, stops taking it.
While these substances are usually taken to promote sleep, they disturb the regular sleep architecture resulting in REM rebound.
REM Rebound and Sleep Apnea
Studies reveal that REM rebound is predominant in people suffering from sleep apnea, especially if they use a CPAP (continuous positive airway pressure) machine.
People using CPAP treatment usually experience changes in their sleep structure like REM rebound, slow-wave sleep rebound and reduced sleep fragmentation.
One study revealed a 57% increase in REM rebound in patients using CPAP treatment for sleep apnea.
Is REM Rebound Harmful?
REM rebound is not harmful and is something everyone has experienced at some point of time in their lives.
It is simply a way by which our brain makes up for lost sleep. However, too much REM sleep can be bad and excessive REM sleep can cause you to feel groggy and tired the next day.
Too much REM sleep could be a sign of some underlying issues such as depression, sleep disorders or some other health problem.
So, if you find yourself sleeping for over 10 hours or that you are in REM sleep most of the night, then it may be a good idea to speak with your medical practitioner.
The Final Word
So, in conclusion, any change in your natural sleep cycle is usually referred to as REM rebound sleep, which is typically caused when the body is deprived of sufficient REM sleep because of various reasons like sleep deprivation, sleep apnea or substance withdrawal.
The brain compensates for sleep deprivation by longer and more frequent REM cycles, which in turn, results in more dreams, which may be more vivid or even nightmarish.
And, before the REM cycle is finished, the body may awaken, which may cause sleep paralysis. Nevertheless, despite all of these things, REM rebound is a normal thing. It is not dangerous and should not be a cause of worry.