Rem Sleep Cycles: Healthy Patterns And Their Benefits

Sleep is a complex and mysterious process that is essential for the body and brain to rest and recover. A healthy sleep cycle typically involves four stages, three non-rapid eye movement (NREM) stages followed by a rapid eye movement (REM) stage. These cycles usually last between 90 and 120 minutes, and a person will go through four to six of them per night. Each stage has a unique function and is crucial for maintaining overall cognitive performance and physical health.

The four stages of sleep

Healthy sleep cycles are important for maintaining your brain's overall cognitive performance. A healthy sleep cycle consists of four stages, three of which are non-rapid eye movement (NREM) sleep, and the fourth is rapid eye movement (REM) sleep.

Stage 1 NREM sleep

Stage 1 is the lightest stage of sleep and usually lasts for about five to ten minutes. During this stage, your brain slows down, and your heartbeat, eye movements, and breathing slow with it. Your body relaxes, and your muscles may twitch.

Stage 2 NREM sleep

Stage 2 is a deeper sleep, during which your heart rate and body temperature drop, and your eye movements stop. Your brain also begins to produce bursts of rapid, rhythmic brain wave activity, known as sleep spindles, which are associated with memory consolidation. Stage 2 typically lasts for about 20 minutes per cycle, and people spend about half of their total sleep time in this stage.

Stage 3 NREM sleep

Stage 3 is the deepest stage of sleep, during which your muscles are completely relaxed, your blood pressure drops, and your breathing slows. This is the stage when your body starts its physical repairs, and you feel refreshed the next day. It is difficult to wake someone up during this stage, and if they do wake up, they may experience sleep inertia, a state of confusion or "mental fog" that can last for up to an hour.

Stage 4: REM sleep

REM sleep is also known as active sleep. During this stage, your brain activity is similar to its activity when you are awake, but your body is temporarily paralyzed, preventing you from acting out your dreams. Your eyes move rapidly behind closed eyelids, and your breathing becomes faster and more irregular. REM sleep typically begins about 90 minutes after falling asleep and is associated with dreaming, memory consolidation, and the processing of emotions and emotional memories.

Non-REM sleep

N2 is the second stage of non-REM sleep, and it is deeper than the first. During this stage, you become less aware of your surroundings, your body temperature drops, your eye movements stop, and your breathing and heart rate become more regular. This stage lasts for about 20 minutes per cycle, and people spend about half of their total sleep time in this stage.

The third and final stage of non-REM sleep is N3, also known as delta sleep or slow-wave sleep. This is the deepest stage of sleep, and it is harder to wake someone up during this phase. Muscle tone, pulse, and breathing rate decrease further as the body relaxes. The brain produces delta waves, which are associated with bodily recovery, growth, and repair. Sleepwalking typically occurs during this stage, which is more common in the early part of the night. N3 sleep is also when the brain consolidates declarative memories, such as general knowledge, facts, and personal experiences.

REM sleep

During REM sleep, your brain is active and your eyes move rapidly in different directions. Your brain activity is similar to when you are awake, and this is the stage of sleep when dreams typically occur. Your muscles are usually limp during this stage, so you don't act out your dreams.

Healthy adults spend around 25% of their sleep in the REM stage, and this increases as the night goes on. The first REM stage is typically the shortest, at around 10 minutes, and later stages can last for up to an hour.

If you don't get enough REM sleep, you may experience symptoms such as trouble coping with emotions, difficulty concentrating, a weakened immune system, and feeling groggy in the morning.

To increase your REM sleep, you need to get more sleep overall. Creating a relaxing bedtime routine, setting a sleep schedule, avoiding nicotine and caffeine, and spending time outside every day are all ways to improve your sleep.

Sleep disorders

• Central disorders of hypersomnolence (e.g. narcolepsy)
• Circadian rhythm sleep-wake disorders (e.g. jet lag, shift work sleep disorder)
• Sleep-disordered breathing (e.g. sleep apnea)
• Sleep-related movement disorders (e.g. restless leg syndrome)
• Parasomnias (disorders that affect either NREM or REM sleep)
• Sleep-related eating disorders

Parasomnias

Parasomnias are a category of sleep disorders that affect either non-rapid eye movement (NREM) or rapid eye movement (REM) sleep. Parasomnias can include:

• Sleep starts or twitches (sleep myoclonus)
• Exploding head syndrome
• Teeth grinding (bruxism)
• Night terrors (sleep terrors)
• Sleepwalking (somnambulism)
• Confusional arousals (partial waking with sleep inertia)
• Nightmares and nightmare disorder
• REM sleep behaviour disorder
• Hypnagogic and hypnopompic hallucinations

REM Sleep Behaviour Disorder

REM sleep behaviour disorder (RBD) is a sleep disorder where the paralysis that normally occurs during REM sleep is incomplete or absent, allowing the person to act out their dreams. RBD is characterised by the acting out of dreams that are vivid, intense, and violent. People with RBD may talk, yell, punch, kick, jump out of bed, or grab during an episode. The person may wake up during an episode and vividly recall the dream that corresponds to their physical activity. RBD is usually seen in middle-aged to elderly people and is more common in men.

The exact cause of RBD is unknown, but it may be linked to degenerative neurological conditions such as Parkinson's disease, multisystem atrophy, and diffuse Lewy body dementia. In some cases, RBD may be caused by alcohol or sedative-hypnotic withdrawal, or the use of certain types of antidepressants.

Treatment of Sleep Disorders

The treatment for sleep disorders can vary depending on the specific disorder and individual circumstances. Some sleep issues may not require any treatment, while others may require lifelong care or treatment. It is important to consult a healthcare professional if you are experiencing issues with sleep, as good quality sleep is essential for health and well-being.

Improving sleep quality

• Optimise your bedroom environment: Minimise noise, light, and artificial light from devices such as alarm clocks. Keep your bedroom at a comfortable temperature; around 65°F (18.3°C) is ideal for most people.
• Get a comfortable bed and mattress: A medium-firm mattress may be a good choice to improve comfort and avoid back pain. Choose bedding based on personal preference.
• Stick to a sleep schedule: Go to bed and wake up at the same time every day, including weekends. This helps regulate your body's circadian rhythm.
• Have a bedtime routine: Reading, low-impact stretching, listening to soothing music, or relaxation exercises can help you wind down and signal to your brain that it's time to sleep.
• Avoid bright lights and electronics before bed: The light from electronic devices can suppress your natural melatonin production. Try to disconnect an hour or more before going to bed.
• Get natural light exposure during the day: Sunlight exposure helps regulate your body's internal clock. If you can't get outside, consider investing in a light therapy box.
• Exercise regularly: Daily exercise improves sleep quality, but avoid intense exercise close to bedtime as it may hinder your body's ability to settle down before sleep.
• Avoid caffeine and alcohol late in the day: Caffeine reduces total sleep time and sleep efficiency, while alcohol negatively affects sleep quality and hormone levels. Avoid consuming caffeinated and alcoholic beverages at least 8 hours and 2 hours before bedtime, respectively.
• Eat dinner a few hours before bed: Eating late at night can disrupt sleep quality. If you need a snack, opt for something light.
• Limit liquid intake before bed: Drinking large amounts of liquids before bed can lead to frequent urination during the night, disrupting sleep.
• Practise relaxation techniques: Mindfulness, meditation, deep breathing, and visualisation can improve sleep quality and are common methods used to treat insomnia.
• Consider supplements: Melatonin supplements can help you fall asleep faster, while other natural sleep aids include valerian, chamomile, and glycine. Always consult a healthcare professional before taking any supplements.

Frequently asked questions