Rem Sleep: Why Am I So Tired?

Sleep is a complex and mysterious process that is essential for the body and brain to rest and recover. While the recommended amount of sleep for adults is 7-9 hours, many people struggle to achieve this, and even when they do, they may still feel tired. This could be due to various factors, such as lifestyle choices, medical conditions, or sleep disorders.

One factor that may contribute to feelings of tiredness is the quality of sleep, including the amount of REM sleep achieved. REM sleep is the fourth stage of sleep, characterised by rapid eye movement, increased brain activity, and dreaming. While it plays a crucial role in memory consolidation, emotional processing, and brain development, too much or too little REM sleep can lead to fatigue and other issues.

Therefore, understanding and optimising one's sleep, including the REM stage, is important for overall health and well-being.

Alcohol and caffeine consumption

Alcohol and caffeine are two of the most widely consumed substances, and they can have significant effects on sleep. Here's how they impact your sleep and what you can do to mitigate their negative consequences:

Alcohol:

• Sleep Disruption: Alcohol is known to disrupt sleep, especially in the second half of the night. While it can help you fall asleep faster, it reduces REM sleep duration, the deepest stage of sleep essential for restoration and memory consolidation. This can lead to grogginess, higher disease risk, and even early death.
• Circadian Rhythm Disruption: Alcohol interferes with your body's natural circadian rhythm, making you feel sleepy when you want to be awake and vice versa. It achieves this by decreasing your body's sensitivity to cues like daylight and darkness, which are crucial for regulating sleep-wake cycles.
• Sleep Disorders: Long-term alcohol use is associated with chronic sleep problems and disorders such as sleep apnea. It can also worsen existing conditions like snoring and sleep apnea, leading to more breathing difficulties during sleep.
• Dehydration: Alcohol has a diuretic effect, causing frequent urination, which can disrupt sleep by increasing the need for bathroom trips throughout the night.
• Vivid Dreams: Drinking before bed increases the likelihood of vivid dreams, nightmares, sleepwalking, and other parasomnias, further impairing the quality of sleep.
• Tolerance: People can quickly develop a tolerance to alcohol's sedative effects, leading to a need for higher amounts to achieve the same sleep-inducing impact.
• Insomnia: Regular drinking is linked to insomnia and other sleep disorders, especially in older adults. Those with alcohol dependence often experience insomnia symptoms, and the opposite is also true, creating a destructive cycle.

To mitigate these negative effects, it is recommended to avoid alcohol close to bedtime, with experts suggesting a cutoff of at least three hours before sleeping.

Caffeine:

• Stimulant and Dehydration: Caffeine is a stimulant that can make you feel more awake, but it can also disrupt your sleep rhythms, leading to problems falling asleep and daytime tiredness. Caffeine also has a diuretic effect, contributing to dehydration, which can make you feel exhausted.
• Adenosine Receptor Blockage: Caffeine blocks adenosine receptors in the brain. Adenosine is a chemical that helps us feel sleepy. When caffeine wears off, the buildup of adenosine can make you feel even more tired.
• Sugar Crash: Adding sugar to your caffeinated drinks can lead to a sugar crash later, resulting in feelings of exhaustion and sluggishness.
• Tolerance and Sensitivity: Regular caffeine consumption can lead to tolerance, reducing its stimulating effects. On the other hand, some people are more sensitive to caffeine, experiencing heightened negative symptoms such as a racing pulse, headaches, jitters, and insomnia.
• Withdrawal: Suddenly stopping caffeine consumption can lead to withdrawal symptoms, including headaches and fatigue. It is recommended to gradually reduce intake to avoid these symptoms.
• Timing: Consuming caffeine on an empty stomach, especially in the morning, can increase cortisol levels, affecting how your body regulates energy and alertness, potentially throwing off your sleep cycle.

To minimize the negative impacts of caffeine on sleep, it is advised to limit consumption, especially close to bedtime. The effects of caffeine can last up to seven hours, so avoiding it in the evening can improve sleep quality. Additionally, reducing sugar intake with caffeinated drinks and staying hydrated can help combat tiredness.

Sleep disorders

Sleep is a complex biological process that is essential for both physical and mental health. While you sleep, your brain and body functions remain active, carrying out important jobs that help you stay healthy and function optimally. Sleep disorders are conditions that disturb your normal sleep patterns, and there are over 80 different types.

• Insomnia: Insomnia is the most common sleep disorder, affecting about one-third of adults. It involves difficulty falling asleep or staying asleep. To be diagnosed with insomnia disorder, sleep difficulties must occur at least three nights a week for at least three months and cause significant distress or impairment in daily functioning.
• Sleep Apnea: Sleep apnea is a breathing disorder characterised by interruptions in breathing during sleep. It can be central sleep apnea, where the brain fails to control breathing properly, or obstructive sleep apnea, which involves repeated episodes of airway obstruction.
• Restless Leg Syndrome (RLS): RLS is characterised by an urge to move the legs, usually accompanied by uncomfortable sensations such as tingling or prickling. It typically begins in the teens or twenties and affects up to 3% of the population.
• Hypersomnia: Hypersomnia is the inability to stay awake during the day. It includes narcolepsy, which causes extreme daytime sleepiness. People with hypersomnia may sleep more than nine hours a day and still feel unrefreshed.
• Circadian Rhythm Disorders: These disorders occur when an individual's sleep-wake rhythms (body clock) become misaligned with the external light-darkness cycle, leading to significant sleep problems and daytime sleepiness. This can be caused by internal factors, such as a person's body clock differing from the light-dark cycle, or external factors like shift work or jet lag.
• Parasomnia: Parasomnias are unusual behaviours during sleep, such as walking, talking, or eating. They can occur during NREM or REM sleep and include sleepwalking, night terrors, and nightmares.

Diagnosing sleep disorders involves a comprehensive assessment, including a patient's medical and sleep history, physical examination, sleep studies, and clinical testing. Treatment options depend on the specific disorder and may include lifestyle changes, cognitive behavioural therapy, relaxation techniques, medications, and the use of devices such as CPAP machines.

Memory consolidation

During REM sleep, your brain prunes its synapses, which are the spaces where brain cells communicate with each other. This process improves your memory and problem-solving abilities. It also aids in mood regulation by helping your brain process emotional memories, including those associated with fear.

While the benefits of REM sleep for memory consolidation are well-known, the underlying mechanisms are still being studied. Some research suggests that REM sleep may not be crucial for certain types of memory, such as explicit or declarative memory, which includes rote memory and language memory. However, other studies indicate that REM sleep plays a key role in language or emotional learning.

The amount of REM sleep needed for memory consolidation varies across individuals and is influenced by factors such as age, stress levels, sleep quality, and sleep duration. On average, adults get around 90 minutes of REM sleep each night, but this can be shorter or longer depending on individual differences and sleep habits.

In summary, REM sleep plays a vital role in memory consolidation, facilitating the conversion of short-term memories into long-term ones. This process contributes to improved cognitive and emotional well-being. However, the specific mechanisms and the extent to which REM sleep is necessary for different types of memory are still subjects of ongoing research.

Emotional processing

Rapid Eye Movement (REM) sleep is important for emotional processing. During REM sleep, the brain transfers short-term memories from the motor cortex to the temporal lobe, converting them into long-term memories. This process is thought to improve memory and problem-solving abilities.

REM sleep also helps the brain process emotional memories, including those associated with fear. Research has shown that REM sleep helps to heal from traumatic experiences by suppressing troubling memories. This is why adequate rest after a stressful day is an integral part of the recovery process.

REM sleep is also 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.

A lack of REM sleep can have a negative impact on emotional processing. Studies have shown that suppressing REM sleep increases negative affect and amygdala responses to social exclusion.

The amount of REM sleep needed varies throughout our lives. Newborns spend about half their sleep time in REM sleep, but this starts to decrease by about 6 months, continuing to decline throughout childhood and the teen years. By age 20, most people spend just over 20% of their total sleep time in REM sleep. In older adults, time spent in REM sleep decreases slightly, to about 17% by age 80.

If you are not getting enough REM sleep, your body will naturally increase it the next night. This is known as REM rebound.

To increase the amount of REM sleep you get, try to get a good night's sleep overall. Most REM sleep occurs at the end of the night, so getting enough total sleep helps to maximise REM sleep.

• Stick to a sleep schedule.
• Limit alcohol and caffeine.
• Stay active.
• Relax before bed.

Brain development

REM sleep is vital for brain development, particularly in infants and children. This is because it is thought to aid in the development of the central nervous system, which includes the brain and spinal cord. Newborns spend about half their sleep time in REM sleep, and this starts to decrease by about six months, continuing to decline throughout childhood and the teen years. By adulthood, the average amount of REM sleep needed is just two hours per night.

REM sleep is also important for brain development because it helps with memory consolidation and emotional processing. During this sleep stage, the brain processes new learnings and motor skills from the day, deciding which to commit to memory and which to delete. The brain also processes emotions during REM sleep, and dreams may be involved in this process.

REM sleep deprivation disrupts the brain's ability to generate new cells, so it is important to get enough of it. However, missing out on REM sleep is not the same as missing out on overall sleep, as the two are not mutually exclusive. It is possible to experience dreams and REM sleep deprivation without experiencing overall sleep deprivation.

Frequently asked questions