Rem Sleep: Myth Or Reality?

Sleep is divided into two stages: REM (rapid eye movement) and NREM (non-rapid eye movement). During REM sleep, the eyes move rapidly, the brain is active, and dreams occur. REM sleep is important for learning, memory, and mood. It is also when the brain repairs itself and processes emotional experiences.

REM sleep was first described in 1953 by Kleitman and Aserinsky, who showed that periods of 'active' sleep in human infants were marked by rapid eye movements. This discovery was a turning point in the way scientists and the medical community viewed the sleeping brain. Today, we know that REM sleep is characterised by various physiological and behavioural markers, including a reduced amplitude and faster frequency cortical electroencephalogram (EEG), high-amplitude theta waves in the hippocampal EEG, active suppression of skeletal muscle activity, and intermittent muscle twitches.

While the amount of REM sleep needed varies across the lifespan, it is clear that it serves an important biological purpose.

What happens to the body during REM sleep?

During REM sleep, the body experiences a unique set of physiological changes that distinguish it from non-REM sleep. The REM stage of sleep is characterised by rapid eye movements, increased brain activity, irregular breathing, elevated heart rate, and muscle relaxation. These changes indicate that the body is in a "wakeful" state, with brain waves similar to those during wakefulness.

During REM sleep, the eyes move rapidly behind closed eyelids, and brain activity increases. The breath rate rises, and the body experiences temporary paralysis, likely to prevent people from acting out their dreams. This stage of sleep is associated with dreaming and memory consolidation. It also plays a role in emotional processing and brain development.

REM sleep is the fourth stage of sleep and typically occurs about 60 to 90 minutes after falling asleep. Throughout the night, the body cycles between non-REM and REM sleep, spending more time in the REM stage as the night progresses. Each cycle through all sleep stages takes 90 to 120 minutes to complete, and a person will usually go through four or five cycles per night.

The amount of REM sleep needed varies across species, with humans requiring approximately two hours per night. Newborns spend up to eight hours in REM sleep each day, while adults only need around two hours.

How does REM sleep benefit brain function?

REM sleep is the fourth out of four total stages of sleep. It is characterised by relaxed muscles, quick eye movement, irregular breathing, elevated heart rate, and increased brain activity.

REM sleep is important for brain function as it plays a role in memory consolidation, emotional processing, brain development, and dreaming.

Memory Consolidation

During REM sleep, the brain processes new learnings and motor skills from the day, committing some to memory, maintaining others, and deciding which ones to delete. This is supported by studies of both humans and animals, which suggest that being deprived of REM sleep interferes with memory formation.

Emotional Processing

REM sleep is also important for emotional processing. Dreams, which are more vivid in REM sleep, may be involved in this process. Additionally, the amygdala, the part of the brain that processes emotions, is activated during REM sleep.

Brain Development

REM sleep may also promote brain development, as newborns spend most of their sleep time in this stage. This is supported by the fact that animals born with less developed brains, such as humans and puppies, spend more time in REM sleep during infancy than those with more developed brains, like horses and birds.

Wakefulness Preparation

REM sleep might also help us get ready to wake up. This could explain why we spend increasing amounts of time in REM sleep as the night progresses and why we are easier to wake up during this stage.

What are the negative effects of a lack of REM sleep?

REM sleep is one of the two major natural sleep stages, characterised by relaxed muscles, quick eye movement, irregular breathing, elevated heart rate, and increased brain activity. It is thought to be important for memory consolidation, emotional processing, brain development, and dreaming.

A lack of REM sleep can have several negative effects on a person's health and cognitive abilities. Firstly, it can lead to fatigue, irritability, changes in mood and memory, and issues with cognition and problem-solving. Secondly, it can affect cardiovascular health and increase the risk of type 2 diabetes. Thirdly, it may also contribute to cancer, stroke, and neurodegenerative diseases like Alzheimer's. Finally, a lack of REM sleep can cause microsleep episodes, which can be dangerous if they occur during activities that require concentration, such as driving.

How can you increase your REM sleep?

REM sleep is the final stage of the sleep cycle, which we enter about 90 minutes after falling asleep. During this stage, the brain is highly active, and the eyes move rapidly behind closed eyelids. It is also the stage of sleep during which we are most likely to dream.

• Stick to a consistent sleep schedule: Going to bed and waking up at the same time every day primes your body for sleep and waking.
• Keep the bedroom cool and dark: A cool, dark bedroom will help you fall asleep faster. A dark room is important as bright lights hinder melatonin production, which leads to disrupted sleep.
• Add aromatherapy to your bedtime routine: Inhaling the scent of essential oils like lavender, bergamot, and cedarwood can calm your nervous system and make you sleepier.
• Try incorporating white noise: White noise blocks out other sounds and can help you fall asleep faster and stay asleep longer.
• Alternatively, try earplugs: If you'd prefer to block out noise rather than add to it, try a pair of earplugs to keep you asleep regardless of what's happening outside.
• Eat more magnesium-rich foods: Magnesium plays an important part in sleep regulation, and nearly half of Americans don't meet their daily recommended dose. Pumpkin and chia seeds, almonds, and spinach are all magnesium-rich foods.
• Cut back on caffeine: Caffeine messes with your sleep cycle and should be avoided in the second half of the day. Remember that black and green teas, and sodas, also contain caffeine.
• Avoid alcohol before bed: Alcohol disrupts your sleep cycle, particularly REM sleep. It takes the body about an hour to process one drink, so plan your evenings accordingly.

What is REM rebound?

REM rebound, also called REM rebound sleep or the REM rebound effect, is a phenomenon in which a person temporarily receives more REM sleep than they normally would. REM sleep is characterised by rapid eye movements and brain activity patterns that are very similar to the patterns we experience while we are awake. It is during this state that most of our vivid dreaming takes place.

REM rebound occurs when the body compensates for lost sleep by increasing REM sleep duration in subsequent sleep cycles. Factors like stress, substance use, and sleep loss can lead to REM rebound. Sleep deprivation is a leading cause of REM rebound sleep. Sleep deprivation occurs when a person does not sleep for the recommended minimum of seven hours each night. Experiencing a stress response can also prompt REM rebound sleep. Researchers theorise that the REM stage of sleep helps people regulate emotions and reframe negative experiences encountered during the day. Obstructive sleep apnea, which causes disrupted sleep, can also lead to REM rebound when using a continuous positive airway pressure (CPAP) machine treatment for the first time.

REM rebound is not necessarily related to REM sleep behaviour disorder, a disorder in which sleepers act out their dreams. Though vivid dreams or nightmares might be a clue, the most accurate way to determine if you are experiencing REM rebound sleep is by having an electroencephalogram (EEG) measure your brain waves as you sleep.

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