Daytime Sleepiness: Understanding The Symptoms And Their Causes

Sleep is a basic human need, but for some people, it can be difficult to stay awake and alert during the day, despite getting a full night's rest. This condition is known as hypersomnia, and it affects a person's ability to function at work and socially, impacting their quality of life and increasing the risk of accidents. The symptoms of hypersomnia include constant sleepiness during the day, sleeping longer than average but still feeling tired, difficulty waking up in the morning or after naps, and a lack of alertness even after napping. While the exact cause of hypersomnia remains unknown in many cases, it is often associated with factors such as genetics, neurotransmitters in the brain, and underlying medical or psychiatric conditions. Treatment options include medications, non-drug therapies, and lifestyle changes to improve sleep quality.

Hypersomnia

Symptoms

People with hypersomnia may experience the following:

• Constant, recurrent episodes of extreme sleepiness during the day
• Sleeping longer than average (10 or more hours) and still feeling sleepy during the day
• "Sleep drunkenness", or difficulty waking up in the morning or after daytime naps, sometimes appearing confused or combative
• Daytime naps that don't lead to improved alertness
• Anxiety and irritability
• Slow thinking, slow speech, difficulty concentrating, and memory problems
• Increased risk of accidents, especially motor vehicle accidents

Causes

The exact cause of hypersomnia is often unknown, but it can be caused by a variety of factors, including:

• Insufficient or inadequate sleep due to long working hours, shift work, family demands, or other lifestyle factors
• Environmental factors such as a snoring partner, a baby that wakes up frequently, noisy neighbours, or an uncomfortable mattress
• Mental states such as anxiety and depression
• Medications and substances such as alcohol, caffeinated drinks, tranquillisers, sleeping pills, and antihistamines
• Medical conditions such as hypothyroidism, oesophageal reflux, nocturnal asthma, chronic pain, epilepsy, encephalitis, multiple sclerosis, Parkinson's disease, obesity, obstructive sleep apnea, and more
• Changes in time zone or jet lag, which can disrupt the internal biological clock
• Other sleep disorders such as sleep apnoea, restless legs syndrome, sleep walking, narcolepsy, and insomnia

Treatment

• Avoiding cigarettes, alcohol, and caffeinated drinks near bedtime
• Following a relaxation routine to prevent night-time anxiety
• Exercising regularly and maintaining a healthy weight
• Eating a well-balanced diet
• Reducing disturbances, such as not watching television in the bedroom
• Maintaining a comfortable sleeping environment
• Establishing a regular sleeping routine
• Taking brief "power" naps during the day to improve alertness

In addition to lifestyle changes, medications such as wakefulness-promoting agents and psychostimulants may be prescribed to treat hypersomnia. It is important to consult a doctor or sleep disorder clinic for advice and treatment.

Sleep Disorders

Insomnia

Characterized by difficulty falling and staying asleep, insomnia is the most common sleep disorder. It often spikes during stressful periods but can become chronic if symptoms persist for three months or longer. Poor sleep habits, environmental changes, medications, and co-occurring medical conditions such as asthma or sleep apnea can aggravate insomnia. Treatment options include cognitive-behavioural therapy, sleep hygiene, and, in some cases, supplementary medications.

Sleep Apnea

Sleep apnea is a breathing disorder where an individual stops breathing for 10 seconds or more during sleep. This disrupts sleep quality and oxygen levels and has been linked to high blood pressure, heart disease, and stroke. Continuous positive airway pressure (CPAP) therapy is the standard treatment, facilitating airflow and preventing airway collapse.

Circadian Rhythm Disorders

These disorders are caused by an internal clock (circadian rhythm) that is out of sync with the external day-night cycle. They can be caused by factors such as jet lag or working night shifts. Treatment involves creating brain cues for rest and wakefulness using melatonin and bright light exposure, along with healthy sleep hygiene practices.

Movement Disorders

Restless Leg Syndrome (RLS) is a common movement disorder, causing tingling or prickly sensations in the legs, along with a powerful urge to move them. It can be triggered by health conditions like kidney disease, iron deficiency, neuropathy, or pregnancy, as well as certain medications. Treatment may include discontinuing contributing drugs, iron supplementation, and symptomatic relief through medication and foot wraps.

Parasomnias

Parasomnias are unusual behaviours during sleep, such as sleepwalking, sleep talking, hallucinations, sleep paralysis, or night terrors. They are more common in children, and treatment focuses on reducing the risk of injury and addressing triggers.

Hypersomnias

Hypersomnias are characterized by excessive daytime sleepiness, with individuals often sleeping over 10 hours a night but still feeling groggy. They may experience sleep attacks or hallucinations. Narcolepsy, a type of hypersomnia, includes the additional symptom of sudden muscle weakness (cataplexy) triggered by strong emotions. Treatment for hypersomnias typically includes a combination of sleep hygiene, napping strategies, driving safety precautions, and stimulant medications.

Sleep Inertia

The exact cause of sleep inertia is unknown, but there are three common theories. The first suggests that sleep inertia is caused by an increase in delta waves in the posterior part of the brain. Delta waves, or slow waves, are most commonly seen in the non-rapid eye movement (NREM) stage of sleep. The second theory points to adenosine, a nucleic acid compound found in the brain, which plays a pivotal role in sleep and wakefulness. The third theory suggests that sleep inertia is caused by a reduction in blood flow to the brain upon waking.

There are several strategies to reduce the effects of sleep inertia. These include consistent wake-up times, exposure to natural light, and gentle alarms. Avoiding alcohol and smoking, napping for short periods, and adjusting the temperature of your sleeping environment may also help. Additionally, caffeine can be effective in reducing sleep inertia when coupled with a short nap.

Sleep-Wake Cycle

The sleep-wake cycle, also known as the circadian rhythm, is a 24-hour cycle that is part of the body's internal clock. This clock runs in the background, carrying out essential functions and processes that affect our mental state, behaviour, and bodily processes.

The sleep-wake cycle is controlled by our biological clocks, which are located in the organs and glands throughout our body. However, a "master clock" in a region of the brain called the suprachiasmatic nucleus (SCN) commands all the other clocks. The SCN is located in the hypothalamus and is sensitive to signals of dark and light.

When our eyes sense the morning light, the SCN triggers the release of cortisol and other hormones to help us wake up. As darkness falls, the SCN sends messages to the pineal gland, which triggers the release of melatonin. Melatonin makes us feel sleepy and ready for bed.

Our body's internal clocks are in sync with certain cues in the environment, such as light and darkness. However, artificial light and caffeine can disrupt this process by giving our bodies false wakefulness cues.

Most people's natural circadian cycles are slightly longer than 24 hours. Some people naturally wake up early, while others stay up late. For example, teenagers often prefer later bedtimes and sleep later in the morning than adults.

As we age, the rhythm and timing of our body clocks decline. Neurons or cells in the brain that promote sleep are lost as part of the ageing process. Conditions such as Alzheimer's disease can also speed up the loss of neurons, making it harder for older adults to stay asleep.

A disruption to the sleep-wake cycle can lead to sleep disorders, such as insomnia, narcolepsy, and hypersomnia. These disorders can affect our mental and physical health and impact our daily lives. Treatment options are available to help manage these disorders and improve sleep quality.

Sleep Hygiene

Optimise your sleep environment

• Keep your bedroom quiet, cool, and dark: A quiet, cool, and dark bedroom can promote better sleep. Consider using earplugs, heavy curtains, or an eye mask to reduce noise and block out light.
• Use comfortable bedding and pillows: Choose bedding and pillows that suit your preferences and ensure comfort throughout the night.
• Try calming scents: Light scents like lavender may induce a calmer state of mind and create a positive space for sleep.

Establish a healthy sleep schedule

• Maintain a fixed wake-up time: Keep the same wake-up time every day, even on weekends, to establish a consistent sleep rhythm.
• Prioritise sleep: Avoid sacrificing sleep for other activities. Calculate your target bedtime based on your wake-up time and stick to it as much as possible.
• Make gradual adjustments: If you need to shift your sleep schedule, make small, gradual changes of up to an hour to avoid disrupting your sleep rhythm.
• Limit naps: While naps can boost energy during the day, they can interfere with nighttime sleep. Keep naps short and in the early afternoon to minimise disruption.

Develop a bedtime routine

• Keep a consistent routine: Follow the same steps each night, such as putting on pajamas and brushing your teeth, to signal to your mind that it's bedtime.
• Wind down before bed: Allocate 30 minutes for calming activities like soft music, light stretching, reading, or relaxation exercises to ease yourself into sleep.
• Dim the lights: Bright lights can hinder melatonin production, so dim the lights or use low lighting before bed to facilitate sleep.
• Unplug from electronics: Take a break from electronic devices 30-60 minutes before bed to reduce mental stimulation and limit blue light exposure, which can disrupt melatonin production.
• Practice relaxation techniques: Instead of forcing yourself to fall asleep, focus on relaxation. Techniques like meditation, mindfulness, and paced breathing can prepare your mind and body for sleep.

Cultivate healthy daily habits

• Get daylight exposure: Sunlight is a key driver of circadian rhythms, which regulate sleep.
• Exercise regularly: Regular exercise improves sleep quality and offers additional health benefits. However, avoid strenuous exercise close to bedtime, as it may interfere with sleep.
• Avoid smoking: Nicotine stimulates the body and disrupts sleep, so it's best to avoid it if you're struggling with sleep.
• Reduce alcohol and caffeine intake: Alcohol may initially promote sleep but can disrupt sleep later in the night. Caffeine, being a stimulant, can keep you wired when you want to rest. Limit these substances, especially in the afternoon and evening.
• Eat a well-balanced diet: Nutritional deficiencies can impact sleep quality, so ensure you're eating a healthy, well-balanced diet.
• Avoid late dinners: Eating a large, heavy, or spicy meal close to bedtime can interfere with sleep as your body is still digesting. Opt for lighter meals or snacks before bed.
• Restrict in-bed activities: Using your bed only for sleep and intimate relations can help build a mental association between your bed and sleep.

Frequently asked questions