Daytime Sleep: A Baffling And Exhausting Conundrum

Sleep is a complex and highly individual process, with a wide range of factors influencing our ability to sleep at certain times. While most people are accustomed to a monophasic sleep schedule, sleeping once a day, usually at night, some people are genetically predisposed to a polyphasic sleep schedule, sleeping multiple times over a 24-hour period. This can be due to a variety of reasons, including shift work, family demands, social life, and sleep disorders such as insomnia, narcolepsy, and sleep apnea. Additionally, factors such as caffeine consumption, exercise, and bedroom environment can also play a role in disrupting sleep patterns. Understanding these factors is crucial for optimizing sleep and promoting overall health and well-being.

Hypersomnia

There are several types of hypersomnia sleep disorders:

• Idiopathic hypersomnia: There is no known cause for this type of hypersomnia.
• Narcolepsy type 2 (without cataplexy)
• Narcolepsy type 1 (with cataplexy)
• Kleine-Levin syndrome (KLS), including menstrual-related hypersomnia
• Hypersomnia and narcolepsy associated with other disorders

The exact causes of hypersomnia vary and can be related to other conditions with additional symptoms. Some possible causes include restless leg syndrome, low mood, mood swings, myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS), alcohol consumption, drugs, and certain medications.

To diagnose hypersomnia, a general practitioner (GP) may ask about possible causes, suggest keeping a sleep diary, or refer the patient to a doctor specialising in sleep disorders. Treatment for hypersomnia depends on the underlying cause and may include medication to help stay awake.

It is important to note that hypersomnia is different from insomnia, which is characterised by difficulty falling asleep and staying asleep. Other sleep disorders include sleep apnea, restless leg syndrome, circadian rhythm disorders, and parasomnia.

Circadian Rhythm Disorders

There are several types of Circadian Rhythm Disorders:

• Delayed Sleep Phase Disorder: Characterised by a preference for sleeping after 2 a.m. and waking up after 10 a.m. This disorder is common in adolescents and young adults, causing difficulty in aligning sleep schedules with work or school obligations.
• Advanced Sleep Phase Disorder: More prevalent in older adults, this disorder involves early sleep and wake-up times, making it challenging to stay awake during the evening hours.
• Irregular Sleep Wake Disorder: Commonly observed in elderly patients with dementia, this disorder is marked by a lack of a consistent sleep and wake cycle. Individuals with this disorder experience irregular sleep patterns throughout the 24-hour period, impacting their daily lives.
• Free-running disorder or non-24-hour sleep-wake disorder: This rare disorder is often seen in individuals with blindness. Without the presence of light as a cue, their sleep period drifts later each day, causing a misalignment with the 24-hour cycle.
• Jet Lag: Travelling across multiple time zones can cause a temporary Circadian Rhythm Disorder as the body struggles to adjust to the new light-dark schedule. Jet lag is associated with insomnia, excessive sleepiness during the day, and mood changes.
• Shift Work Sleep Disorder: Affecting those who work unconventional hours, this disorder arises when a person's circadian rhythm cannot adjust to their unusual sleep-wake schedule. This results in insomnia, tiredness, and accidental napping during work hours.

Insomnia

Sleep is a complex biological process. While you are sleeping, your brain and body functions are still active, performing important jobs to help you stay healthy and function at your best. Sleep disorders are conditions that disturb your normal sleep patterns. There are more than 80 different sleep disorders, with insomnia being the most common.

There are different types of insomnia:

• Sleep-onset insomnia: People have difficulty falling asleep when they cannot relax their mind and continue to think and worry. This can also occur when the body is not ready for sleep, with the body's internal clock being out of sync with the earth's cycle of light and dark.
• Sleep maintenance insomnia: People with this type fall asleep normally but wake up several hours later and cannot fall asleep again easily. They may drift in and out of a restless, unsatisfactory sleep. This type of insomnia is more common among older adults and may be caused by substance use, certain medications, or sleep disorders such as sleep apnea or periodic limb movement disorder.

Treatment

The treatment for insomnia depends on its cause and severity but typically involves a combination of treating any underlying disorders, cognitive-behavioural therapy, and good sleep hygiene practices. Cognitive-behavioural therapy can help people understand their problem, unlearn bad sleeping habits, and eliminate unhelpful thoughts. Sleep hygiene practices include establishing a regular sleep-wake schedule, following a relaxing bedtime routine, and making the environment conducive to sleep.

Circadian Rhythm Sleep 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 results in abnormal sleep patterns, sleep loss, and fatigue. There are several types of circadian rhythm sleep disorders, including:

• Delayed Sleep Phase Disorder: This occurs in "night owls" who prefer to sleep after 2 am and wake up after 10 am. This disorder is common in adolescents and can lead to difficulty falling asleep and waking up at times conducive to school and work.
• Advanced Sleep Phase Disorder: This is more common in older adults or "morning larks", who prefer early sleeping and waking times. This makes it difficult for them to stay awake through the evening hours.
• Irregular Sleep Wake Disorder: This is 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 cannot sleep through the night.
• Free-running disorder or non-24-hour sleep-wake disorder: This rare disorder is seen more commonly in individuals with blindness. Without light perception, the sleep period drifts later and later each day, causing a misalignment with the body's internal clock.
• Jet Lag: This occurs during air travel when traversing time zones faster than the body clock can adjust, resulting in a mismatch between preferred sleep and waking times.
• Shift work sleep disorder: This is caused by unconventional work schedules that require individuals to remain awake during their preferred sleep times. As a result, they experience sleepiness while at work and insomnia during their available sleep time.

Treatment

Circadian rhythm sleep disorders can be treated effectively with appropriately timed bright light exposure, sleep scheduling, and other behavioural modifications. Melatonin may also be beneficial for these disorders under the supervision of a specialised sleep medicine physician.

Sleep Apnea

There are a number of reasons why someone might only be able to sleep during the day. One potential cause is a circadian rhythm disorder, which is when your internal clock is disrupted, causing your sleep to become fragmented and scattered across a 24-hour period. This can include shift work sleep disorder, which is caused by working unconventional hours, or jet lag, which occurs when travelling across time zones.

Another possible cause is a sleep disorder called hypersomnia, which is characterised by excessive daytime sleepiness and the need to sleep at irregular times. Idiopathic hypersomnia is a type where there is no known cause, and those who have it wake up feeling confused or irritable, rather than refreshed.

However, one of the most pertinent sleep disorders associated with daytime sleeping is sleep apnea. Sleep apnea is a common condition where your breathing stops and starts many times while you sleep, preventing your body from getting enough oxygen. This can cause you to feel excessively sleepy during the day and only able to sleep at certain times. There are two types of sleep apnea:

• Obstructive sleep apnea (OSA) - the most common type, caused when the upper airway becomes blocked during sleep, reducing or stopping airflow. This can be caused by obesity, large tonsils, or changes in hormone levels.
• Central sleep apnea - caused when the brain does not send the signals needed to breathe. This can be caused by health conditions that affect how the brain controls the airways and chest muscles.

If you are experiencing symptoms of sleep apnea, it is important to talk to a healthcare professional, as it can lead to issues with concentration, decision-making, memory, and behaviour control. It can also increase the risk of stroke and heart attack if left untreated.

Restless Leg Syndrome

The sensations of RLS typically occur when an individual is inactive and sitting or lying down for extended periods. People with RLS may need to keep their legs in motion to minimise or prevent the sensations, such as by pacing the floor or constantly moving their legs while sitting. Symptoms tend to worsen at night, interrupting sleep and making it difficult to fall asleep or return to sleep after waking up. Leg movement or walking typically provides temporary relief from the discomfort, but the sensations often return as soon as movement stops.

RLS symptoms can vary from person to person and can range from moderate to severe. With moderate RLS, symptoms might occur once or twice a week but can cause significant sleep problems and affect daytime functioning. Severe cases of RLS occur more than twice a week.

People with RLS may experience exhaustion and daytime sleepiness, trouble concentrating, memory issues, decreased productivity, and increased risk of depression and anxiety. RLS can develop at any age but typically begins in middle age and is more common in women. While the exact cause of RLS is unknown, it is often genetic and may be related to low iron levels in the brain or dysfunction in the basal ganglia, a part of the brain that controls movement using the neurotransmitter dopamine.

There is no cure for RLS, but treatment can help manage symptoms. The first step is to address any underlying conditions that may be worsening RLS, such as diabetes, neuropathy, sleep apnea, or iron deficiency. Lifestyle changes that may provide relief include reducing the use of alcohol, nicotine, and caffeine, maintaining a regular sleep schedule, moderate exercise, leg massages or warm baths, and the use of heating pads or ice packs. Doctors may also prescribe medications such as anti-seizure drugs, opioids, benzodiazepines, dopaminergic agents, or iron therapy if there is an iron deficiency.

Frequently asked questions