Daytime Sleepiness: Why Can't I Stay Awake?

Feeling sleepy during the day can be a symptom of an underlying health issue. The most common cause of excessive daytime sleepiness is sleep deprivation. However, it can also be caused by sleep disorders, medications, mental health disorders, neurodegenerative diseases, and neurodevelopmental disorders. Hypersomnia, a condition that makes it hard to stay awake during the day, is characterised by extreme daytime sleepiness despite getting an adequate amount of nighttime sleep. If you are experiencing hypersomnia, it is important to seek help from a healthcare professional.

Sleep disorders like insomnia, sleep apnea, and narcolepsy

Insomnia

Insomnia is a disorder characterised by difficulty falling or staying asleep, early awakening, or a sensation of unrefreshing sleep. It can be a standalone disorder or a symptom of other disorders. Acute emotional stressors, such as job loss or a death in the family, can cause insomnia. Inadequate sleep hygiene, such as consuming caffeine or stimulant drugs, exercising or engaging in exciting activities late in the evening, and maintaining an irregular sleep-wake schedule, can also contribute to insomnia.

Sleep Apnea

Sleep apnea is a disorder characterised by fragmented sleep, with individuals waking up frequently throughout the night. Obstructive sleep apnea is a type of sleep apnea that falls under the category of sleep maintenance insomnia, where individuals have difficulty maintaining sleep and experience early awakening.

Narcolepsy

Narcolepsy is a chronic neurological disorder that affects the brain's ability to control sleep-wake cycles. People with narcolepsy experience excessive daytime sleepiness (EDS) and may also suffer from insomnia, with fragmented sleep at night, making it difficult to stay asleep for extended periods. This is due to the disruption of the sleep-wake cycle, resulting in less distinct boundaries between wakefulness and sleep. Individuals with narcolepsy often enter rapid eye movement (REM) sleep much faster than usual, sometimes within 15 minutes of falling asleep. They may also experience muscle weakness or dream activity associated with REM sleep while they are awake.

There are two main types of narcolepsy: Type 1 narcolepsy, previously known as narcolepsy with cataplexy, and Type 2 narcolepsy, previously known as narcolepsy without cataplexy. Type 1 narcolepsy is characterised by low levels of hypocretin, a natural chemical that helps maintain wakefulness and controls REM sleep. Type 2 narcolepsy usually presents with normal hypocretin levels and less severe symptoms.

Lack of sleep or poor sleep quality

Poor sleep quality can also be caused by:

• Sleep disorders, such as insomnia, sleep apnea, or restless leg syndrome
• Mental health disorders, such as depression, bipolar disorder, or anxiety
• Neurological conditions, such as narcolepsy or Parkinson's disease
• Neurodegenerative diseases, such as dementia
• Pain caused by ailments such as arthritis or fibromyalgia
• Frequent nighttime urination (nocturia)
• Medications, especially sedatives, antidepressants, pain medications, and antihistamines
• Withdrawal from drugs or alcohol
• Not maintaining good sleep habits, such as avoiding exercise and caffeine before bed

Underlying health issues, such as depression, anxiety, or ADHD

Excessive daytime sleepiness (EDS) is a common symptom of several underlying health issues, including depression, anxiety, and ADHD.

Depression is a recognised cause of EDS, with many depressed patients seeking medical attention to help manage their sleepiness. A study found that 44.8% of depressed patients experienced EDS, and there is evidence to suggest that EDS and depression may be linked genetically.

Anxiety can also cause EDS due to the hormonal rush that often accompanies this condition. When you feel anxious, your body releases a surge of hormones to prepare you to fight, flee, or freeze, which can leave you feeling drained and tired once the stress stops. Additionally, anxiety can cause sleep disturbances, making it difficult to fall asleep or stay asleep, which can contribute to daytime sleepiness.

While there is limited direct evidence linking ADHD to EDS, it is known that stimulant drugs used to treat ADHD can cause hypersomnia when withdrawn.

If you are experiencing EDS, it is important to consult a healthcare professional to determine the underlying cause and receive appropriate treatment.

Medication side effects, including sedatives and antidepressants

Feeling sleepy during the day can be a side effect of taking certain medications, including sedatives and antidepressants.

Sedatives

Sedatives are often used to treat anxiety or insomnia. They work by stimulating a chemical in the brain called GABA, which leads to sedation, muscle relaxation, and reduced anxiety. However, they can cause side effects such as drowsiness, dizziness, and balance problems, which can negatively impact your ability to drive, work, or perform daily tasks. It is important to use caution when taking sedatives and to avoid mixing them with other sedatives or alcohol due to the risk of overdose.

Antidepressants

Antidepressants can also cause drowsiness as a side effect, although this varies depending on the specific type of antidepressant. For example, fluoxetine (Prozac) can be stimulating and make it hard to fall asleep, while paroxetine (Paxil) can be more sedating and cause sleepiness. Older antidepressants like tricyclic antidepressants and MAOIs tend to have more side effects than newer types such as SSRIs, SNRIs, and atypical antidepressants.

Additionally, some people experience lower alcohol tolerance when taking antidepressants, and combining the two may result in an extra sedative effect. Other side effects may include lower sodium levels, which can cause headaches or confusion, and an increased risk of bleeding due to the impact on platelet clotting.

If you are experiencing excessive drowsiness or other side effects from your medication, it is important to consult your doctor or pharmacist. They may recommend adjusting the dose, changing the medication, or taking the medication at a different time of day.

Lifestyle factors, e.g. caffeine, alcohol, and irregular sleep schedules

Lifestyle factors such as caffeine and alcohol consumption, as well as irregular sleep schedules, can significantly impact your ability to stay awake during the day.

Caffeine

Caffeine is a stimulant widely consumed in the form of coffee, tea, energy drinks, or other caffeinated beverages. While it can enhance performance and improve alertness, excessive caffeine intake or consumption close to bedtime can disrupt sleep and lead to sleep deprivation. The effects of caffeine on sleep quality and daytime functioning are complex and depend on various factors, including individual differences in tolerance and metabolism. However, it is important to note that caffeine withdrawal can also lead to negative consequences, such as deficits in cognitive and emotional processes and increased risk of accidents. Therefore, regulating caffeine intake and avoiding consumption close to bedtime are essential for maintaining a healthy sleep-wake cycle.

Alcohol

Alcohol consumption before bed can disrupt sleep and lead to frequent wakings and low-quality sleep. It can alter your sleep architecture by increasing deep sleep and reducing REM sleep initially and causing more light sleep and fragmented sleep later in the night. Additionally, alcohol can interfere with circadian rhythms and contribute to the development of chronic sleep problems and disorders like sleep apnea. Heavy alcohol use is associated with insomnia, and individuals often turn to caffeine to counteract excessive sleepiness during the day, creating a cycle that further disrupts sleep. Therefore, it is recommended to avoid alcohol close to bedtime and limit overall consumption to improve sleep quality and daytime alertness.

Irregular Sleep Schedules

Maintaining a consistent sleep schedule is crucial for regulating your body's sleep-wake cycle. Irregular sleep patterns can disrupt your circadian rhythm, leading to difficulty sleeping at night and excessive daytime sleepiness. This misalignment between your sleep schedule and the natural day-night cycle can result in sleep deprivation, which has various negative consequences on your health and daily functioning. It can increase the risk of accidents, impair work performance, and lead to mood disorders and other health conditions. Therefore, establishing a regular sleep schedule and improving sleep hygiene, such as managing light exposure and avoiding caffeine and alcohol close to bedtime, can help improve sleep quality and daytime alertness.

Frequently asked questions