Daytime Sleep: To Nap Or Not To Nap?

Sleep is a complex and mysterious process that is essential for the body and brain to rest and recover. While the ideal amount of sleep varies from person to person, most adults require seven to nine hours of sleep per night. Sleeping too much or too little can have negative consequences for your health and well-being. Napping during the day, for example, can disrupt your sleep quality at night and increase the risk of certain health issues. If you're experiencing sleep difficulties, it's important to consult a healthcare professional to rule out any underlying conditions and ensure you're getting the right amount of sleep for your needs.

The pros and cons of daytime napping

Daytime napping can be beneficial, but it also has its drawbacks. Napping has been a common practice in many cultures throughout history, and it can be a great way to boost energy levels and improve alertness during the day. However, napping for too long or at the wrong time of day can disrupt your nighttime sleep and potentially increase the risk of certain health problems.

The pros of daytime napping

Napping can be a great way to boost your energy levels and improve alertness, especially if you didn't get enough sleep the night before. A short nap of 20–30 minutes can improve cognitive performance and help you feel more awake and focused. Napping can also be a way to make up for lost sleep due to factors such as shift work or jet lag. In some cultures, napping is also seen as a social activity or a way to show hospitality to guests.

The cons of daytime napping

One of the main drawbacks of daytime napping is that it can disrupt your nighttime sleep. If you nap for too long or too close to bedtime, you may find it harder to fall asleep at night, or your nighttime sleep may be less restful. This can lead to a cycle of sleep deprivation and increased napping during the day.

Additionally, excessive daytime napping may be a sign of an underlying health condition. If you find yourself needing frequent or prolonged naps, it could indicate a sleep disorder or another medical issue. Excessive napping has been linked to an increased risk of cardiovascular disease and other health problems. Therefore, it's important to discuss any concerns about your sleep habits with a healthcare professional.

Overall, while daytime napping can be beneficial in certain situations, it's important to find a balance that works for you and to prioritize getting a full night's rest whenever possible.

Sleep cycles and stages

The human body cycles through two phases of sleep: rapid eye movement (REM) and non-rapid eye movement (NREM). Each phase and stage of sleep includes variations in muscle tone, brain wave patterns, and eye movements. The body cycles through all stages approximately four to six times each night, with each cycle averaging 90 minutes.

The first stage of NREM sleep, N1, is the lightest stage of sleep and lasts around one to five minutes, comprising 5% of total sleep time. During this stage, the body has not fully relaxed, though body and brain activities start to slow, with periods of brief movements.

The second stage, N2, is deeper sleep, where the heart rate and body temperature drop. This stage is characterised by sleep spindles and K-complexes, which are believed to be integral to synaptic plasticity and memory consolidation. N2 sleep lasts around 25 minutes in the first cycle and lengthens with each successive cycle, eventually comprising about 45% of total sleep.

The third stage, N3, is the deepest stage of sleep, also known as slow-wave sleep (SWS). This stage is characterised by delta waves, which are brain waves with lower frequencies and higher amplitudes. N3 sleep is considered the most difficult to awaken from and is critical for bodily recovery and growth, as well as immune system reinforcement. N3 sleep makes up about 25% of total sleep time in adults, but the duration decreases with age.

After cycling through the three stages of NREM sleep, the body then enters REM sleep, which is associated with dreaming and increased brain activity. The first REM cycle is typically short, around 10 minutes, but each cycle increases throughout the night, with later cycles lasting up to an hour. REM sleep makes up about 25% of total sleep in adults.

Effects of Sleep Deprivation

While pulling an all-nighter or staying up late may provide short-term benefits, it can have significant drawbacks and lasting effects on physical and mental well-being. Sleep deprivation can cause cognitive impairment, increased mood swings, and a higher sensitivity to pain and illness. It can also lead to more long-term issues such as difficulties at work or school, increased risk of anxiety and depression, and a higher risk of chronic illnesses.

Sleep debt and deprivation

Sleep debt, or sleep deficit, is the difference between the amount of sleep your body needs and the amount of sleep you actually get. For example, if your body needs eight hours of sleep per night but you only get six, you have accumulated two hours of sleep debt.

Sleep debt can add up quickly from common activities like working, commuting, socialising, relaxing, and watching TV. Even going to sleep 20 or 40 minutes later than usual for a few days can quickly add up.

The consequences of sleep debt can be severe. If you don't get enough sleep on a regular basis, you might feel tired throughout the day, lose your ability to remain focused and efficient, and weaken your immune system. Sleep debt can also make it more difficult for your brain to process and store new information. Research has shown that people can adapt to chronic sleep restriction without feeling particularly sleepy, even though their body is showing significant declines in physical and mental performance.

Being in a prolonged state of sleep debt or sleep deprivation on a regular basis increases the risk of diabetes, hypertension, heart disease, and stroke. Sleep deprivation is also linked to reduced immune function, metabolic dysregulation and weight gain, and a greater risk of falls and accidents. Prolonged sleep deprivation also affects memory and cognitive functions.

To avoid sleep debt, it's important to learn how much sleep your body needs and improve your sleep hygiene. This includes keeping a set sleep schedule, developing a nightly routine, reconsidering your daytime habits, and improving your bedroom environment.

If you're already in sleep debt, taking naps, sleeping in on the weekends, and reconsidering your relationship with sleep can help. However, it's important to note that it can take several days to recover from sleep debt, and sleeping in on the weekends may not fully compensate for the negative effects of sleep loss.

Sleep disorders

Sleep is a complex biological process that is critical to both physical and mental health. While you are sleeping, your brain and body functions are still active, performing important jobs that help you stay healthy and function at your best. Sleep disorders are conditions that disturb your normal sleep patterns, and there are more than 80 different types.

Insomnia

The most common sleep disorder, insomnia, involves problems falling and staying asleep. To be diagnosed with insomnia disorder, sleep difficulties must occur at least three nights a week for at least three months, causing distress or problems at work, school, or other areas of daily life. About one-third of adults report insomnia symptoms, and 4-22% meet the criteria for insomnia disorder.

Sleep Apnea

A breathing disorder characterised by interruptions in breathing during sleep lasting 10 seconds or more. Sleep apnea can cause snoring, snorting, gasping, or breathing pauses. It is diagnosed with a clinical sleep study and is treated with lifestyle changes, mouthpieces, or a CPAP device.

Restless Leg Syndrome (RLS)

RLS involves a tingling or prickly sensation in the legs, along with a powerful urge to move them. It usually occurs during periods of rest or inactivity and is relieved by movement. RLS can cause difficulty falling asleep and frequent awakenings, leading to daytime sleepiness.

Hypersomnia

Hypersomnia is characterised by an inability to stay awake during the day. This includes narcolepsy, which causes extreme daytime sleepiness. People with hypersomnia sleep for long periods and have difficulty staying awake after abruptly waking up.

Circadian Rhythm Disorders

These are problems with the sleep-wake cycle, making it difficult to sleep and wake at the right times. Circadian rhythm disorders can be caused by internal factors, such as a person's body clock being different from the light-dark cycle, or external factors like shift work or jet lag.

Parasomnia

Parasomnia involves acting in unusual ways while falling asleep, sleeping, or waking from sleep, such as walking, talking, or eating. Examples include sleepwalking, night terrors, and nightmare disorder.

Non-Rapid Eye Movement (NREM) Sleep Arousal Disorders

These involve episodes of incomplete awakening from sleep, usually during the first third of a major sleep episode, accompanied by sleepwalking or sleep terrors. They cause significant distress and problems with functioning.

Rapid Eye Movement (REM) Sleep Behaviour Disorder

This disorder involves episodes of arousal during sleep associated with speaking and/or movement, often in response to events in a dream. These behaviours can cause injury to the individual or their bed partner and lead to social isolation or work-related problems.

The science of sleep

Sleep is vital for the proper functioning of the body and mind. Staying awake for 24 hours is known as total sleep deprivation and can have some extensive and potentially serious consequences.

The body's internal sleep and wake cycle is driven by two factors: sleep drive and the circadian clock. Sleep drive is the urge to sleep that increases the longer you stay awake. The circadian clock is the body's internal 24-hour schedule that controls the rhythms of biological functions like hormone levels, digestion, and body temperature. Typically, these two factors align, but they can clash, such as when you take a nap that interferes with your usual bedtime.

The body's biological clock is set by the suprachiasmatic nucleus (SCN), a collection of 20,000 neurons in the brain's hypothalamus. At dawn, light travels through the eyelids to the SCN, which then instructs the brain to release cortisol, the hormone that helps you stay alert. Cortisol levels gradually drop after sundown, and the SCN tells the pineal gland to release melatonin, the hormone that makes you feel sleepy.

Disruptions to the circadian clock can be caused by substances like caffeine and alcohol, certain medications, inconsistent schedules, jet lag, mental health conditions, and working night shifts.

The immediate negative consequences of sleep deprivation on cognitive function include impaired memory, alertness, judgement, and decision-making. Sleep deprivation can also lead to increased feelings of anxiety, depression, anger, and confusion.

Additionally, sleep is when the body repairs muscles, and sleep deprivation can alter this process, leading to increased fatigue and lower energy levels. Research also shows that going without sleep for 24 hours increases sensitivity to pain, pressure, and cold temperatures.

Sleep deprivation can also impact the immune system, making the body less able to fight off illness and increasing the risk of chronic illnesses. It can also contribute to type 2 diabetes, unintentional weight gain, dyslipidemia, hypertension, and cancer.

To get back on a healthy sleep schedule, it is recommended to maintain sleep hygiene practices, such as keeping your bedroom dark at night and exposing yourself to bright light in the morning.

Frequently asked questions