Have you ever woken up feeling lost as what day of the month or time of the day it is because you had a very long and eventful (thanks to the adventurous dream you also had) sleep? You probably experienced a “REM rebound” — a period of increased rapid-eye-movement (REM) sleep due to prior periods of sleep deprivation or other stressors.
Sleep is a complex and essential process that helps the body refresh and recharge itself. Suppose, for some reason, your body starts lacking its needed sleep duration. In that case, it’ll start adding up your sleep debt and let many other processes in your body pay for it (in excessive daytime sleepiness, fatigue, irritability, confusion, mood swings, sluggishness, lower attention span, etc.) until you start having a sufficient amount of sleep quantity (around 7-9 hours, for most healthy adults).
The same happens when you don’t get adequate rapid eye movement (REM) sleep. In this case, when your body has the chance, it’ll spend more time in REM sleep (what is known as REM rebound) to make sure it pays up your REM sleep debt.
But what even is REM sleep?
Most healthy people cycle through four stages of sleep throughout the night: NREM (non-rapid eye movement) 1, NREM 2, NREM 3 (AKA, deep sleep), and REM sleep. REM sleep, the state where dreams are most likely to occur, is a sleep state that is thought to generally regulate emotions and consolidate memory. According to the American Sleep Association, three things are associated with REM sleep: limited to no muscle activity (known as muscle atonia, thought to occur so we don’t act out our dreams), rapid eye movements, and dreams.
Research states that REM sleep takes up about 20% to 25% of total sleep time and happens every 90 to 120 minutes of a night’s sleep. A person may go through four to five cycles of REM sleep in one night, although longer periods of REM sleep are more likely to occur during the second half of the night. Research observes that REM sleep helps with mental and emotional recovery from traumatic experiences by suppressing troubling memories through “reverse learning or remodeling process.”
Because there is a sleep deprivation epidemic, chances are: you’ve experienced REM rebound, as well as many other people.
What is REM Rebound?
REM rebound happens when the body stays in the REM sleep stage longer than it usually would. According to the Journal, Hormones and Behaviour, it’s the body’s response to stress and sleep deprivation. When you don’t get enough REM sleep, your body compensates itself by increasing the frequency, depth, and intensity of your REM sleep when it can.
So, instead of REM sleep state taking up only around 20% to 25% of total sleep time, it could take up to 58% of sleep time. Studies suggest that a 20% increase in REM sleep time is a marker of REM rebound in people with obstructive sleep apnea (OSA) who begin continuous positive airway pressure (CPAP) treatment.
- Corticotropin-releasing Hormone (CRH)
- Plasma Corticosterone
- Corticotropin-Like Intermediate Peptide (CLIP)
- Prolactin (PRL)
- Serotonin (5-HT)
What Causes the REM Rebound Effect?
REM rebound primarily happens when the body is stressed or sleep-deprived. According to the Journal of Clinical Sleep Medicine, five factors may cause an increase in REM sleep time, including: REM sleep deprivation, withdrawal of REM-suppressing recreational drugs, withdrawal of REM suppressing drugs, depression, and undergoing CPAP treatment.
Let’s look into them.
1. Sleep Deprivation
Sleep deprivation is one of the major reasons why you may experience REM rebound, particularly as the body won’t also be getting needed REM sleep. Studies suggest that when a person continually doesn’t get enough REM sleep, it’ll attempt to recover “REM sleep-enriched sleep” whenever the opportunity comes.
The more sleep deficit a person has, the more likely their sleep architecture will change to accommodate more REM sleep. Research suggests that people who don’t get enough sleep for 12 to 24 hours will have increased REM and deep sleep when they finally do.
Stress is another widely acknowledged reason why a person may experience the REM rebound effect. According to an article published in the EXCLI journal, depending on the nature and severity of the stressor, stress can trigger different responses on the body, from altering a person’s sleep architecture to severe illnesses.
Stress and sleep have a two-way relationship. Insufficient sleep may exert stress on the body, while acute stress may trigger REM rebound—with chronic stress ultimately affecting overall sleep quality.
Numerous studies suggest that increased REM sleep state is the body’s recovery response to negative and stressful experiences: “Go to bed because you’ll feel better in the morning.” For example, evidence found that victims of motor vehicle accidents who got more REM sleep episodes didn’t later have PTSD. Plus, a 2019 study found that the most distinct effect of acute stress is longer REM sleep time.
3. Withdrawal of REM Suppressing Recreational Substances and Alcohol
Some recreational substances like cocaine, marijuana, and alcohol may suppress REM sleep. So, when a person stops taking them, they can experience the REM rebound effect.
Evidence shows cocaine and amphetamine are stimulants that disturb sleep and reduce REM sleep and overall sleep time. When a person abruptly discontinues use, they may experience excessive daytime sleepiness and REM rebound.
Tetrahydrocannabinol (THC)—a psychoactive constituent of cannabis— in high dose may reduce REM sleep. A 2020 study comparing reduced REM sleep percent in heavy marijuana users and non-marijuana users found that marijuana users had significantly lower REM sleep than non-marijuana users.
According to an article published in the Journal, Advances in Experimental Medicine and Biology, alcohol, even in moderate amounts, can reduce REM sleep. Once a person stops intaking alcohol, they’ll first experience an increase in REM before returning to the average REM sleep duration.
4. Withdrawal of REM Suppressing Drugs
REM suppressing drugs may restrict REM sleep time, so when a person abruptly stops taking them, they may experience a remarkable increase in REM sleep state.
For example, antidepressants, especially those with anticholinergic properties, produce the REM rebound effect after discontinuation. Also, some medications for treating sleep disorders, like barbiturates, significantly reduce REM sleep time. If a person stops them, it also means their REM sleep time will go up.
Depression is a mental health condition, and one of its distinctive symptoms is poor sleep. Studies suggest that depression alters sleep architecture by reducing deep sleep and disrupting REM sleep. People with depression may experience higher REM sleep duration and intensity. Little wonder studies suggest that REM sleep deprivation in people with depression may improve the condition.
REM sleep quantity has been identified as a marker of depression, that may identify relapse and remission in a person with depression.
6. Starting CPAP Treatment
People with obstructive sleep apnea (OSA), a condition in which the upper airway intermittently collapses all through the night, continually experience sleep deprivation because of this sleep disorder. So when they begin CPAP treatment (the gold standard for preventing OSA episodes), they immediately show increased REM sleep state, taking up as much as 58% of total sleep time.
Similarly, a 2014 study showed that a 34-year-old man who had OSA had a substantial increase in REM sleep after undergoing CPAP treatment that took up 72% of his total sleep time.
How Can You Tell If You’re Experiencing the REM Rebound Effect?
The best way to tell if you’re experiencing the REM rebound effect is by seeing a doctor who may conduct a thorough clinical evaluation of sleep disturbances and related pathology that may cause REM rebound.
But people who experience REM rebound may have longer, more vivid dreams while asleep and may wake up feeling disorientated, confused, and with a headache.
Treating underlying sleep disorders and maintaining healthy sleep hygiene may help improve REM sleep and bring it to baseline, which is usually 20 to 25% of total sleep. Consider consulting with a doctor if you suspect that you may have a sleep disorder so they can recommend appropriate treatment for your case and improve your sleep health.