Daytime Sleepiness: Why Am I Falling Asleep?

Feeling sleepy during the day can be a symptom of a variety of issues, from a lack of sleep to underlying medical conditions. If you're experiencing excessive daytime sleepiness, it's important to address the problem, as it can interfere with your work and social life, and even put you at risk of accidents. While it may be tempting to blame your sleepiness on a busy lifestyle, there could be a more serious cause. Read on to discover some of the reasons why you might be falling asleep during the day.

Why am I falling asleep during the day?

Sleep Disorders

Falling asleep during the day could be a sign of a sleep disorder. Sleep disorders are conditions that negatively impact a person's ability to sleep well at night, resulting in excessive daytime sleepiness. Sleep disorders can have various causes, including medical conditions, lifestyle factors, and environmental factors.

One common sleep disorder is obstructive sleep apnea (OSA), which occurs when an obstruction in the upper airway makes it difficult for a person to breathe, causing them to wake up periodically with gasping or snorting noises. Another sleep disorder is restless legs syndrome (RLS), which causes an urge to move the legs during periods of inactivity, particularly in the evenings. RLS is often associated with unpleasant or uncomfortable sensations in the legs.

Other sleep disorders that may contribute to excessive daytime sleepiness include insomnia, sleep apnoea, sleep walking, and narcolepsy. Insomnia is characterised by difficulty falling or staying asleep, while sleep apnoea involves periodic interruptions in breathing during sleep. Sleep walking is more common in children, and narcolepsy is a brain disorder that causes excessive sleepiness and can lead to sudden sleep attacks during activities.

In addition to these specific sleep disorders, more generalised sleep disturbances can also lead to daytime sleepiness. This can include inadequate sleep, which may be due to shift work, family demands, or social life. Environmental factors, such as noise, temperature, and light, can also impact sleep quality and contribute to daytime sleepiness.

If you are experiencing excessive daytime sleepiness, it is important to consult a medical professional for advice and potential treatment options.

Medication

Some medications can cause daytime sleepiness as a side effect. These include:

• Antidepressants
• Antihistamines, found in sleep aids or medicines that treat allergies
• Antiemetics, which are used to control nausea and vomiting
• Antipsychotics and anticonvulsants, which can be used to treat seizures or depression
• Drugs to treat high blood pressure, including alpha-blockers and beta-blockers
• Benzodiazepines and other sedatives, commonly used for anxiety or insomnia
• Drugs for Parkinson's disease
• Muscle relaxants
• Opioids and other prescription pain medications
• Over-the-counter medicines for insomnia, allergies, nausea, vomiting, or diarrhea

If medication is the cause of your daytime sleepiness, you should talk to your doctor about it. They may suggest adjusting the dosage or changing the medication. They may also recommend a natural sleep aid like melatonin or a prescription sleeping pill.

If medication is not the cause, there are still medications that can be used to treat daytime sleepiness. These include:

• Wakefulness-promoting agents like modafinil (Provigil®), armodafinil (Nuvigil®), pitolisant (Wakix®), and solriamfetol (Sunosi®)
• Psychostimulants like amphetamine, methylphenidate (Ritalin®, Daytrana®, Methylin®, Concerta®) or dextroamphetamine (Procentra, Dexedrine, Zenzedi)
• Sodium oxybate (Xyrem® or Xywav®), flumazenil (Romazicon®), and clarithromycin (Biaxin®)

Medical Conditions

Excessive daytime sleepiness can be a symptom of an underlying medical condition. Hypersomnia is a condition characterised by extreme sleepiness during the day, despite getting an adequate amount of sleep at night. It can be caused by other medical conditions, including epilepsy, hypothyroidism, encephalitis, multiple sclerosis, Parkinson's disease, obesity, obstructive sleep apnea, delayed sleep phase syndrome, multiple systems atrophy, myotonic dystrophy, and other genetic disorders. It can also be caused by head trauma, tumours, and central nervous system diseases.

Other medical conditions that can cause excessive daytime sleepiness include:

• Obstructive sleep apnea, which causes difficulty in breathing due to an obstruction in the upper airway.
• Restless legs syndrome, which causes an urge to move the legs during periods of inactivity, particularly in the evenings.
• Electrolyte imbalances, such as sodium, potassium, calcium, phosphate, and magnesium deficiencies, can cause extreme tiredness.
• Anaemia, which is when the body does not have enough haemoglobin, a protein that helps red blood cells carry oxygen throughout the body.
• Depression, which can disrupt sleep and cause people to sleep too much.
• High or low blood sugar levels can interfere with sleep and cause daytime drowsiness.
• Thyroid disorders can increase the time it takes to fall asleep, reduce sleep, and increase sleep disruptions.
• Chronic kidney disease can lead to a reduction in sleep quality and an increased rate of sleep disorders.
• Narcolepsy, a brain disorder that makes people feel sleepy most of the time and can cause them to fall asleep suddenly and unexpectedly.

Environmental Factors

Noise Pollution

Noise from vehicles, construction, or even animals can significantly disrupt sleep. These noises can make it difficult to fall asleep, stay asleep, or result in lower quality sleep. Using earbuds or a white noise machine can help cover or distract from unwanted sounds.

Temperature

The body's internal temperature and the surrounding environment strongly influence sleep. Being too hot or cold can interfere with sleep, and everyone has unique temperature preferences. Research suggests maintaining a bedroom temperature between 66–70°F (18.8–21.1°C) may be optimal for sleep.

Light Exposure

The body's sleep-wake cycle is linked to the sun's daily cycle. Exposure to light two hours before bedtime or during sleep can delay sleepiness. It can be challenging to fall and stay asleep in bright environments. Using blackout curtains or eye masks can help block out light for improved sleep.

Work Schedules

Shift work, particularly night shifts, can be detrimental to sleep quality. Working at night and sleeping during the day contradicts the normal human sleep-wake cycle, leading to sleep difficulties. It also causes desynchronization with the body's internal clock or circadian rhythm.

Home Environment

Various factors in your home environment can contribute to broken sleep. For example, a snoring partner, a baby that wakes up frequently, noisy neighbours, or an uncomfortable mattress can interrupt your sleep.

Lifestyle Factors

The most common reason for falling asleep during the day is a lack of sleep. Most people need 7–9 hours of sleep per day, and when someone does not get enough, their body may force them to fall asleep to catch up.

Some lifestyle habits that can disrupt sleep include:

• Not going to bed at the same time each day
• Using electronic devices before bed
• Consuming large meals before bed
• Drinking alcohol or caffeinated drinks near bedtime
• Exposure to light 2 hours before bedtime or during sleep
• Working night shifts

Making a regular sleep schedule and routine and sticking to it usually helps improve sleep quality.

Frequently asked questions