The Mystery Of Rem Sleep: Who Sleeps More?

Sleep is a complex and mysterious process that is essential for the human body and brain to rest and recover. During sleep, we cycle through different stages, including rapid-eye movement (REM) sleep, which is known for its association with dreaming. REM sleep is characterised by increased brain activity, rapid eye movement, irregular breathing, and elevated heart rate. While the amount of REM sleep needed varies across age groups, it generally plays a crucial role in memory consolidation, emotional processing, and brain development.

REM sleep and memory consolidation

REM sleep is vital for 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.

REM sleep is characterised by relaxed muscles, quick eye movement, irregular breathing, elevated heart rate, and increased brain activity. The first REM episode usually lasts for just a few minutes, lengthening during each subsequent sleep cycle. Towards the end of the night, one may spend up to half an hour in REM sleep.

REM sleep is also important for improved learning, mood regulation, brain development, and protection against dementia. During REM sleep, the brain prunes its synapses, the spaces in which brain cells communicate with one another. This appears to improve memory and problem-solving abilities.

REM sleep is also when most dreams occur. However, dreams are not exclusive to REM sleep.

REM sleep and emotional processing

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. It plays a role in memory consolidation, emotional processing, brain development, and dreaming.

REM sleep is important for regulating our emotions. Our brains process emotions during REM sleep, and dreams, which are more vivid in REM sleep, may be involved in emotional processing. The amygdala, the part of the brain that processes emotions, activates during REM sleep.

REM sleep deprivation affects emotional reactivity and social function. Negative emotional reactivity is enhanced and positive reactions to positive events are often subdued.

REM sleep deprivation has been found to increase negative affect and decrease positive affect. It also impairs the consolidation of emotional memories.

REM sleep suppression increases general negative affect and enhances amygdala responses and alters its functional connectivity with the anterior cingulate cortex during passively experienced experimental social exclusion.

REM sleep and brain development

REM sleep is vital for brain development, especially in newborns and young children. During this stage of sleep, the brain prunes its synapses, improving memory and problem-solving abilities. REM sleep also helps the brain process emotional memories, including those associated with fear, and is thought to aid in the development of the central nervous system.

REM sleep is characterised by relaxed muscles, quick eye movement, irregular breathing, elevated heart rate, and increased brain activity. During this stage, the eyes move rapidly behind closed eyelids, and the muscles in the arms and legs become temporarily paralysed, preventing people from acting out their dreams.

Research has shown that sleep deprivation during early development negatively impacts brain maturation. Newborns spend about half their sleep time in REM sleep, and this gradually decreases over childhood and the teen years. By age 20, most people spend just over 20% of their total sleep time in REM sleep, and this further decreases to about 17% by age 80.

REM sleep is also important for memory consolidation and emotional processing. It is associated with the consolidation of new learnings and motor skills from the day, committing some to memory and deleting others. REM sleep is also when most dreams occur, and these dreams are usually more vivid than those during non-REM sleep.

Overall, REM sleep plays a crucial role in brain development, especially in early life, and insufficient REM sleep may have negative consequences for cognitive and emotional functioning.

REM sleep and dreaming

REM sleep, or rapid eye movement sleep, is a stage of the sleep cycle characterised by relaxed muscles, quick eye movement, irregular breathing, an elevated heart rate, and increased brain activity. It usually occurs 90 minutes after falling asleep, with the first period being the shortest at around 10 minutes. Each subsequent REM stage gets longer, with the final one lasting up to an hour.

During REM sleep, the brain is highly active, with brain waves resembling those of wakefulness. The eyes move rapidly, and the muscles in the arms and legs become temporarily paralysed, preventing sleepers from acting out their dreams. This stage of sleep is also associated with dreaming and memory consolidation.

REM sleep plays a vital role in several functions, including:

• Memory Consolidation: During REM sleep, the brain processes new learnings and motor skills from the day, committing some to memory and deciding which ones to delete.
• Emotional Processing: The brain processes emotions during REM sleep, and the amygdala, responsible for processing emotions, is activated.
• Brain Development: Researchers hypothesise that REM sleep promotes brain development, especially in newborns, who spend most of their sleep time in this stage.
• Wakefulness Preparation: The activation of the central nervous system during REM sleep may help prepare the body to wake up. This could explain why people spend increasing amounts of time in REM sleep towards the end of the night and why they are easier to wake up during this stage.

The amount of REM sleep needed varies with age. Newborns spend about half their sleep time in REM sleep, which gradually decreases to about 20% for most people by the age of 20. Older adults experience a slight decline, with REM sleep making up about 17% of their total sleep by the age of 80.

REM sleep and mental health

REM sleep, or rapid eye movement sleep, is the fourth of four stages of sleep. It is characterised by relaxed muscles, quick eye movement, irregular breathing, elevated heart rate, and increased brain activity. Most adults need about two hours of REM sleep each night.

The Benefits of REM Sleep

REM sleep plays a key role in brain health and function. It aids in brain development, mood regulation, and memory consolidation.

Brain Development

REM sleep is thought to aid in the development of the central nervous system, which includes the brain and spinal cord. This may be why infants, particularly newborns, require so much REM sleep.

Mood Regulation

REM sleep helps the brain process emotional memories, including those associated with fear. Studies have shown that people who get less REM sleep may have a greater risk of developing dementia.

Memory Consolidation

During REM sleep, the brain processes new learnings and motor skills from the day, committing some to memory and deciding which ones to delete.

REM Sleep Behaviour Disorder (RBD)

REM sleep behaviour disorder is a parasomnia, or sleep disorder, in which people physically and/or vocally act out their dreams while in the REM stage of sleep. The person is unaware of their actions, and this can lead to accidental injury to themselves or their bed partner. RBD is most common in people over the age of 50, and it affects men nine times more than women.

The Link Between REM Sleep and Mental Health

Depression and Anxiety

Studies have shown that REM sleep is altered in people with depression and anxiety. Depressed or anxious participants who were awakened during REM sleep reported more negative self-appraisals and recalled more negative memories. They also experienced more negative dreams, which may be linked to suicidal ideation.

Dementia

As mentioned earlier, a lack of REM sleep may increase the risk of developing dementia.

Nightmare Disorder

People with nightmare disorder regularly experience intense and distressing nightmares, which usually occur during REM sleep. This can be brought on by stress, childhood trauma, and other frightening experiences.

REM sleep plays an important role in mental health and overall brain function. While REM sleep is typically restorative, in some cases, such as with RBD, it can be disruptive and even dangerous. Therefore, it is important to address any issues with sleep to ensure overall health and well-being.

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