Rem Sleep: Why Does It Always Arrive Late?

REM sleep is a crucial stage of the sleep cycle, characterised by rapid eye movement, brain activity similar to wakefulness, and muscle relaxation. While the average adult needs about two hours of REM sleep per night, the timing of REM sleep can vary. If you find that your REM sleep is consistently late, it could be due to a variety of factors, including sleep disorders, substance use, certain medications, or exposure to artificial light before bed. To optimise your sleep schedule and ensure you're getting adequate REM sleep, it's important to maintain good sleep hygiene practices, such as sticking to a consistent sleep schedule, avoiding screen time before bed, and creating a relaxing sleep environment.

Alcohol, caffeine, and tobacco consumption

REM sleep is a crucial stage of sleep, associated with dreaming, memory consolidation, and brain development. While it typically occurs in the second half of the sleep cycle, certain substances like alcohol, caffeine, and tobacco can delay or disrupt this stage, leading to impaired sleep quality and quantity.

Alcohol consumption, especially in moderate to high amounts, can delay the onset of REM sleep and reduce the overall time spent in this stage. Drinking alcohol within four hours of bedtime can lead to disrupted sleep, frequent awakenings, night sweats, nightmares, and headaches. Binge drinking can also affect melatonin levels for up to a week, impacting the body's sleep-wake cycle.

Caffeine, a stimulant, can interfere with a good night's rest by blocking brain chemicals that promote sleep. It can make it harder to fall asleep, cause lighter sleep with more frequent awakenings, and increase the need to use the toilet during the night. Caffeine's effects can last up to 24 hours in the body, and even those who believe they have built a tolerance may still experience impaired sleep. It is recommended to limit caffeine intake to no more than 200 mg per day and avoid it for at least 3 to 7 hours before bedtime.

Tobacco use, particularly smoking cigarettes, can also negatively impact sleep. Nicotine is a stimulant that makes it harder to fall asleep and stay asleep. It is advisable to avoid cigarettes altogether, or at least refrain from smoking for at least 2 hours before bedtime.

Additionally, there is research suggesting a positive association between sleep bruxism (involuntary teeth grinding) and the consumption of alcohol, caffeine, and tobacco.

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 (e.g. sleep myoclonus, sleepwalking, nightmares)
• Sleep disorders associated with REM sleep (e.g. REM sleep behaviour disorder, narcolepsy, nightmare disorder)

If you are experiencing sleep issues, it is recommended that you seek professional medical advice. A healthcare provider can help determine the root cause of any underlying sleep issues and develop a treatment strategy to improve your sleep.

Medication

• Antidepressants
• Antibiotics
• Antihypertensives
• Oral contraceptives
• Thyroid replacements
• Decongestants
• Weight loss agents
• Ginseng preparations
• High-dose vitamin B1

Additionally, the use of certain medications can increase the occurrence of specific sleep disorders. For example, the use of lithium has been linked to an increase in arousal disorders such as sleepwalking. It is important to note that medication can also be used to treat sleep disorders, including:

• Sedatives and hypnotics for insomnia
• Amphetamines for daytime sleepiness
• Continuous positive airway pressure (CPAP) for obstructive sleep apnea
• Dopamine agonists for restless legs syndrome and periodic limb movement disorder
• Melatonin for circadian rhythm disturbances

Screen time before bed

Blue Light Exposure

Screens emit blue light, which is known to suppress melatonin production. Melatonin is a crucial hormone responsible for regulating sleep and controlling your sleep-wake cycle. Exposure to blue light can affect your internal body clock and disrupt your circadian rhythm, which is your body's way of telling you when to sleep and when to wake up. This disruption can lead to insomnia and other sleep problems.

Overstimulation of the Brain

When you engage in activities like scrolling through social media or watching exciting videos before bed, your brain becomes stimulated. Instead of relaxing and preparing for sleep, it is busy processing all the information, making it harder to fall asleep and delaying REM sleep. This overstimulation can keep you awake for hours beyond your normal bedtime.

Sleep-Wake Cycle Disruption

Excessive screen use over time can upset your body's natural sleep-wake rhythm or circadian rhythm. This disruption can lead to insomnia and other sleep disorders. It is important to make a conscious effort to fix your sleep schedule and establish a healthy bedtime routine that does not involve screen time.

Mood and Emotional Impact

Tips for Reducing Screen Time Before Bed:

• Create a screen-free zone in your bedroom. Keep your devices out of the bedroom or at least stick to audio content like white noise or a sleep story.
• Set a technology curfew and put your devices away at least an hour before bedtime.
• Use blue light filters or external filters, and wear blue-light-filtering glasses to reduce blue light exposure.
• Stick to a supportive bedtime routine that includes relaxing activities such as listening to music, reading a physical book, journaling, or sipping chamomile tea.

Sleep deprivation

• Trouble concentrating and decreased cognitive performance: Sleep deprivation can lead to difficulties with focus and concentration during the day. This is because your working memory is highly affected by a lack of sleep. In particular, short sleepers who regularly get fewer than six hours of sleep a night can experience impairments in their working memory similar to those who have pulled two all-nighters in a row.
• Excessive daytime sleepiness: When you don't get enough sleep, you may experience excessive sleepiness during the day, making it hard to stay awake and alert. This can be dangerous if it occurs while driving or operating machinery.
• Mood changes: Sleep deprivation can affect your mood, leading to irritability, anxiety, or depression. This is partly due to the role of REM sleep in emotional processing.
• Poor immune system function: Sleep helps your body repair itself and boost its immune system. Not getting enough sleep, including REM sleep, can leave you more vulnerable to illness.
• Metabolic problems and increased risk of Type 2 diabetes: Sleep deprivation has been linked to metabolic issues and an increased risk of developing Type 2 diabetes.
• Weight gain and obesity: There is a link between chronic sleep deprivation and weight gain, which can increase the risk of obesity.
• Cardiovascular disease: Research suggests that long-term sleep deprivation may contribute to the development of cardiovascular disease.
• Cognitive impairment: Over time, a lack of sleep can lead to cognitive impairment and problems with brain function.
• Impaired memory and learning: REM sleep plays a crucial role in memory consolidation and learning. Deprivation of REM sleep can disrupt the brain's ability to form new memories and process information.
• Impaired creativity: REM sleep is associated with enhanced creativity, and not getting enough of it may impact your ability to think creatively.
• Decreased problem-solving abilities: The dreaming and brain activity that occurs during REM sleep are important for problem-solving and making connections.
• Mental health issues: REM sleep is essential for mental health maintenance, and deprivation can lead to or exacerbate mental health problems.
• Increased risk of dementia: Studies have found a link between reduced REM sleep and an increased risk of developing dementia.

To mitigate the negative consequences of sleep deprivation, it is important to prioritize sleep and practice good sleep hygiene. This includes maintaining a consistent sleep schedule, limiting screen time before bed, exercising regularly, and creating a relaxing sleep environment. If you are struggling with sleep deprivation or suspect you may have a sleep disorder, it is important to consult a healthcare professional for guidance and support.

Frequently asked questions