Excessive Daytime Sleepiness: Symptoms, causes, and treatments

Feeling tired isn’t uncommon. According to the National Sleep Foundation’s 2020 Sleep in America Poll, almost half of Americans feel sleepy from three to seven days a week.

But if you regularly experience extreme tiredness during the day that impairs your ability to function or regularly need to take naps, you could be suffering from excessive daytime sleepiness (EDS). 

Approximately 20% of Americans experience excessive daytime sleepiness, and it’s often a side effect of another sleep disorder or underlying health condition.

Sleep deprivation can lead to a range of health difficulties, so it’s important to identify and treat the underlying cause. Continue reading to discover the symptoms and causes of excessive daytime sleepiness and treatment options available.

Table of Contents

What is excessive daytime sleepiness?

Excessive daytime sleepiness, also referred to as hypersomnia, is the strong urge to fall asleep during hours that you should be awake. 

It’s characterized by the American Academy of Sleep Medicine as “the inability to maintain wakefulness and alertness during the major waking episodes of the day, with sleep occurring unintentionally or at inappropriate times almost daily for at least three months.”

You may have excessive daytime sleepiness if you:

  • Regularly fall asleep during the day
  • Regularly nap during the day and wake up feeling unrefreshed
  • Feel sleepy even though you sleep for long hours at night

Fatigue or sleepiness?

The terms ‘fatigue’ and ‘sleepiness’ are often used interchangeably, and while individuals with EDS may experience fatigue, there are differences between the two. 

Fatigue is characterized by a lack of physical and mental energy, whereas daytime sleepiness is the feeling of needing to sleep (and sometimes actually falling asleep) that can impair daytime functioning. 

Someone with sleepiness may fall asleep when inactive, but those with fatigue are often unable to initiate sleep when resting.

excessive daytime sleepiness

Types of excessive daytime sleepiness

As with many sleep disorders, excessive daytime sleepiness can fall into two categories:

  • Primary hypersomnia: caused by narcolepsy or idiopathic hypersomnia (EDS with no known cause)
  • Secondary hypersomnia: usually caused by a sleep disorder or medical condition

Symptoms of excessive daytime sleepiness

The symptoms of excessive daytime sleepiness include:

  • Decreased alertness
  • Irritability
  • Memory impairment
  • Difficulty concentrating 
  • Difficulty making decisions
  • Decreased reaction times
  • Risk-taking behaviors

Consequences of excessive daytime sleepiness

Sleep deprivation is one of the most serious symptoms of sleep disorders due to the impact it can have on day-to-day functioning. Some of the consequences of EDS include:

  • Increased risk of motoring accidents
  • A decline in work or academic performance
  • Social and relationship problems
  • Decreased productivity
  • Mood disturbances 
  • Poor quality of life
excessive daytime sleepiness

Causes of excessive daytime sleepiness

There are many causes of excessive daytime sleepiness, which can make reaching a diagnosis tricky, but the causes usually fall into the following categories:

  • Sleep deprivation 
  • Sleep disorders
  • Medical and psychiatric conditions 
  • Medications 

Sleep deprivation

Unsurprisingly, insufficient sleep is a leading cause of excessive daytime sleepiness. There are many variables that can cause a lack of sleep, including sleep disorders, medical conditions or medications, lifestyle factors (e.g. working hours), or environmental factors that cause fragmented sleep (e.g. a new baby or loud sleep environment. Individuals who work shifts often experience excessive daytime sleepiness.

Sleep disorders

Various sleep disorders can cause excessive daytime sleepiness as a result of interrupted or insufficient sleep. These include sleep-related breathing disorders (e.g. obstructive sleep apnea), sleep-related movement disorders (e.g.restless leg syndrome), and circadian rhythm sleep-wake disorders (e.g. jet lag).

Hypersomnias of central origin (primary hypersomnia)

Though less common, excessive daytime sleepiness can also be caused by:

  • Narcolepsy (the most common cause of primary hypersomnia)
  • Kleine-Levin syndrome 
  • Menstrual-related hypersomnia
  • Idiopathic hypersomnia 

While these are types of sleep disorders, the excessive sleepiness experienced is not caused by sleep deprivation as it is with other sleep disorders.

Medical conditions

Certain medical conditions and neurological disorders have been linked to excessive daytime sleepiness, including Parkinson’s disease, multiple sclerosis,  hypothyroidism, obesity, and hepatic encephalopathy. Often, uncovering and treating the medical condition can ease symptoms of daytime sleepiness.

Psychiatric conditions

Psychiatric conditions such as depression (most commonly) and anxiety can result in excessive daytime sleepiness.

Medications and substances

Medications such as hypnotics or sedatives are known to cause excessive daytime sleepiness. These include anticonvulsants, antidepressants, antihistamines, antipsychotics, benzodiazepines, beta-blockers, and muscle relaxants. Smoking and alcohol can also contribute to EDS.

excessive daytime sleepiness

Treatment and management of excessive daytime sleepiness

Reaching an EDS diagnosis and identifying the underlying cause is the first step in treating the disorder. The underlying cause will also determine the best-suited treatment route.

Sleep hygiene

When EDS is caused by insufficient sleep due to lifestyle or environmental factors, teaching patients about good sleep hygiene and implementing a bedtime routine can help. This includes:

  • Going to bed and waking up at the same time every day 
  • Relaxing before bed
  • Keeping a comfortable and quiet sleep environment 
  • Avoiding caffeine, alcohol, and smoking
  • Exercising regularly, but not too close to bedtime
  • Avoiding big meals before bed

As well as the above steps, scheduling brief naps throughout the day can help ease symptoms, especially for individuals with narcolepsy.

Treating underlying sleep disorders

Identifying and treating any underlying sleep disorders can reduce daytime sleepiness. 

Obstructive sleep apnea

For patients with EDS caused by obstructive sleep apnea, treatments include continuous positive airway pressure (CPAP), mouthpieces, or surgery. 

Restless leg syndrome

When EDS is caused by RLS, medications such as iron supplements, dopamine agonists, or benzodiazepines may be prescribed.

Circadian rhythm sleep-wake disorders

For those with EDS as a result of a circadian rhythm sleep-wake disorder, light therapy, lifestyle changes (such as the bedtime hygiene tips above), and supplements like melatonin can help. For individuals with jet lag, taking steps to minimize the severity, like setting your watch to the local time and only sleeping at certain times, can help.

Treating underlying medical or psychiatric disorders

In cases where EDS is caused by an underlying medical or psychiatric condition, taking steps to diagnose and treat the disorder can reduce sleepiness. For example, in patients with depression or anxiety, therapy or medication may be recommended by a doctor.

Reviewing existing medication

Reviewing existing medication that could be causing EDS and changing the dose or type can help improve or eliminate symptoms.


In individuals with primary hypersomnia (where the cause is unknown), treatment is usually aimed at minimizing sleepiness and helping patients stay awake when they are supposed to be. Stimulants like modafinil (Provigil) may be prescribed to help with this.

excessive daytime sleepiness

Getting an excessive daytime sleepiness diagnosis

Reaching an EDS diagnosis can be difficult because it’s different to ‘feeling tired all the time’ or feeling fatigued, so differentiating between these is vital.

To gain an accurate diagnosis, your doctor will likely:

  • Try to identify the cause of your sleepiness, e.g. medical or psychiatric conditions, medicines you may be taking, lifestyle factors, etc.
  • Evaluate your sleep history to identify any sleep disorders (e.g. uncomfortable leg sensations, snoring, waking up gasping for breath)
  • Carry out a physical examination – things like excessive yawning, struggling to keep eyes open, difficulty concentrating, or falling asleep while in the waiting room could indicate EDS
  • Use the Epworth Sleepiness Scale (ESS) – an ESS >10 often indicates EDS and >17 indicates severe EDS
  • Ask you to keep a sleep diary 
  • Refer you to a sleep disorder specialist

Lack of sleep can be extremely hazardous, putting sufferers at risk of serious harm. If you feel overwhelmingly sleepy during hours that you should be awake, and it’s affecting your daily life, we recommend seeking medical advice as soon as possible.

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