Daytime Sleep: A Comfortable Slumber's Mystery

Sleep is a complex biological process that is essential for maintaining physical and mental health. However, some people experience better sleep during the day instead of at night. This phenomenon can be attributed to various factors, including circadian rhythm disorders, delayed sleep phase syndrome, insomnia, stress, anxiety, depression, poor sleep habits, and lifestyle choices. Circadian rhythm disorders occur when the internal clock in the brain is not synchronized with local time, resulting in abnormal sleep patterns. Delayed sleep phase syndrome, a type of circadian rhythm disorder, causes individuals to fall asleep and wake up late, often in the early morning hours. Insomnia, a common sleep disorder, can be caused by stress, anxiety, depression, or certain medications. Lifestyle choices such as caffeine and alcohol consumption, irregular schedules, and aging can also impact sleep quality. Understanding and addressing these factors are crucial for improving sleep patterns and overall well-being.

Delayed Sleep Phase Syndrome (DSPS)

DSPS can significantly impact an individual's life, causing impairment in social, occupational, or other areas. The prevalence of this condition is notable among adolescents and young adults, with approximately 7 to 16% experiencing it. It may develop in early childhood but typically emerges or worsens during adolescence. Some adolescents delay their sleep schedules for social reasons, and their sleep patterns usually normalise in early adulthood.

The primary symptoms of DSPS include:

• Not falling asleep at the desired bedtime, which is aligned with societal norms.
• Difficulty waking up at the desired time, which is in line with societal expectations.
• Severe daytime sleepiness.
• Issues with memory, focus, and concentration.
• Behavioural and/or mood changes, such as irritability.

DSPS is a type of circadian rhythm sleep disorder, where the internal body clock, or the circadian rhythm, is misaligned with the external day/night cycle. This misalignment results in abnormal sleep patterns, sleep loss, and fatigue. The condition can be effectively treated with bright light therapy or chronotherapy, which gradually shifts the individual's sleep pattern to a more conventional schedule.

If you suspect you may have DSPS, it is advisable to consult a healthcare professional or a sleep disorder specialist. They can recommend appropriate treatments to help reset your internal clock and improve your sleep patterns.

Circadian Rhythm Disorders

Circadian rhythm sleep disorders occur when the circadian clock in the brain, which drives daily behavioural and physiological rhythms, is not synchronised with 'real' local time. This can result in abnormal sleep patterns, sleep loss, and fatigue.

The timing, duration, and quality of sleep are determined by two physiological processes: the sleep homeostat, which measures the need to sleep, and the circadian clock, which drives the daily, 24-hour body rhythms in all aspects of physiology and behaviour, including the sleep/wake pattern.

The time we go to bed and wake up is generally determined by our work, study, and social commitments. For those who work or study on a 9 a.m. to 5 p.m. pattern, a 'normal' sleep schedule would involve going to bed between 10 p.m. and midnight and waking up between 6 a.m. and 8 a.m. However, those with circadian rhythm sleep disorders have internal clocks that are not synchronised with such a 'normal' sleep schedule. This leads to problems in falling asleep, staying asleep, and feeling fully rested, as well as feeling sleepy during waking hours.

There are several types of circadian rhythm sleep disorders:

• Delayed Sleep Phase Disorder occurs in "night owls" when the preferred time for sleep is typically after 2 a.m., with a wake-up time after 10 a.m. This disorder results in difficulty falling asleep and waking up at times conducive to school and work. When individuals with this disorder attempt to wake up earlier, they become sleep-deprived and may experience impaired alertness. Delayed Sleep Phase Disorder is most common in adolescents.
• Advanced Sleep Phase Disorder is more common in older adults, or "morning larks", when the internal clock prefers early times for sleeping and waking. This makes it difficult to stay awake through the evening hours, and those with this disorder often wake up much earlier than desired.
• Irregular Sleep Wake Disorder is most commonly seen in elderly patients with dementia and refers to a lack of rhythm in a person's sleep and wake cycle. Sleep occurs irregularly throughout a 24-hour period, and individuals with this disorder cannot sleep through the night and have difficulty maintaining wakefulness during the day.
• Free-running disorder or non-24-hour sleep-wake disorder is rare and more commonly seen in individuals with blindness. Bright morning light (sunrise) aligns our internal clock to the 24-hour day. When light perception is absent, the sleep period drifts later and later each day, causing this disorder.
• Jet lag occurs during air travel when we traverse time zones faster than our body clocks can adjust, causing a mismatch between the preferred sleep and waking times and the destination sleep and waking times.
• Shift work sleep disorder is due to an unconventional work schedule that causes people to remain awake during preferred sleep times. As a shift worker, individuals may experience sleepiness while at work and insomnia during the time available to sleep. Other symptoms include difficulty concentrating, headaches, and low energy levels while awake.

Circadian rhythm sleep disorders can be treated with appropriately timed bright light exposure, sleep scheduling, and other behavioural modifications. While melatonin is not yet FDA-approved, it may be beneficial for circadian rhythm sleep disorders under the supervision of specialised sleep medicine physicians.

Insomnia

Circadian rhythm disorders are a less common cause of insomnia. People who abuse drugs or alcohol often suffer from insomnia.

If you are experiencing insomnia, it is recommended that you consult a healthcare professional.

Depression and anxiety

Sleep and depression are closely linked, and the two can have a bidirectional relationship. Poor sleep may create difficulties regulating emotions, leaving you more vulnerable to depression, while depression is associated with sleep difficulties.

How Sleep Affects Depression

Poor sleep can make it more difficult to cope with stress and regulate emotions, making you more vulnerable to depression. Sleep problems are often the first sign of depression. Even minor sleep issues can drag your mood down, and the more serious a problem like insomnia gets, the more likely you are to become depressed.

How Depression Affects Sleep

Depression might mean you have a hard time falling asleep or staying asleep. It can even change how long you spend in the different sleep stages. For example, depression has been linked to sleep disorders such as insomnia and obstructive sleep apnea. Research suggests that most people living with major depression have some type of sleep difficulty.

Breaking the Cycle

Together, sleep problems and depression can create a cycle that's hard to break. Common treatments for depression may not work when you have sleep issues, and depression is more likely to return if you don't address your sleep problems. However, there is some evidence that treating sleep problems can help alleviate depressive symptoms. Cognitive behavioural therapy for insomnia (CBT-I), along with depression treatment, may improve sleep in people with depression and increase the chances of remission.

Sleep environment

Creating a peaceful sleep environment can help you sleep better. Here are some tips to optimise your sleep environment:

• Avoid working late into the night: Working late into the night can disrupt your sleep schedule and make it difficult to fall asleep. Try to establish boundaries and stick to a consistent sleep schedule as much as possible.
• Maintain a set routine before bed: Developing a bedtime routine can help signal to your body that it's time to wind down and prepare for sleep. This routine can include activities such as reading a book, listening to soothing music, or practising relaxation techniques such as deep breathing or meditation.
• Avoid stimulating activities before bed: As your bedtime approaches, avoid engaging in stimulating activities such as strenuous exercise, playing video games, or watching thrilling movies or shows. Opt for calming activities that promote relaxation instead.
• Avoid heavy meals, caffeine, and alcohol before bed: Consuming heavy meals, caffeine, or alcohol before bedtime can interfere with your sleep. Caffeine and alcohol can disrupt your sleep schedule and impact your sleep quality. Finish your dinner a few hours before bedtime and opt for a light, easily digestible snack if you need one.
• Create a comfortable bedroom environment: Ensure your bedroom is cool, dark, and quiet. Consider using blackout curtains, earplugs, or white noise machines to create a peaceful and comfortable sleep environment.
• Establish a consistent sleep schedule: Go to bed and wake up at the same time every day, including weekends. This helps to regulate your body's internal clock and improve your overall sleep quality.
• Avoid daytime napping: If you have trouble sleeping at night, avoid napping during the day. While napping can provide a quick energy boost, it can also disrupt your nighttime sleep, especially if you're already struggling with sleep issues.
• Seek professional help if needed: If you continue to have difficulty sleeping, consider consulting a healthcare professional or a sleep specialist. They can provide personalised advice and guidance to help you improve your sleep habits and address any underlying sleep disorders or conditions.

Frequently asked questions