Excessive Daytime Sleepiness

Updated on November 1, 2019

It’s the middle of the day, and you’re in an important meeting or class. You need to pay attention, but you just can’t keep your eyes open. No matter how hard you might try to focus, drowsiness sets in, and it feels like heavy weights are pulling your eyelids shut.

Most people have experienced this situation every once in awhile, but for some, estimated at around 20% of adults, this becomes a persistent problem known as excessive daytime sleepiness or EDS. People with EDS struggle to stay awake during normal waking hours, and it can negatively impact their work and social life and put them at an elevated risk of all types of accidents.

This guide examines excessive daytime sleepiness in detail. It explains what EDS is as well as its symptoms, health consequences, and causes. It also reviews how EDS is diagnosed and how it may be treated so that people with this problem can be empowered to take steps to address it.

What is Excessive Daytime Sleepiness?

Unlike many medical problems with complicated or technical names, excessive daytime sleepiness is straightforward. As the name indicates, EDS is when a person is constantly sleepy and has difficulty staying awake during the day.

What Are the Symptoms of Excessive Daytime Sleepiness?

The clearest and most obvious symptom of EDS is drowsiness during daylight hours. It is often accompanied by mood changes like irritability as well as cognitive problems related to focus and concentration.

Many people who have excessive daytime sleepiness describe having a feeling of fatigue. Fatigue, though, can have a vaguer colloquial use and should be thought of as distinct from EDS. While being drowsy can be part of fatigue, fatigue also commonly reflects bodily weakness, pain, or disability. EDS, though, is specifically related to feeling sleepy.

What Are the Consequences of Excessive Daytime Sleepiness?

The main consequences of excessive daytime sleepiness come from how it can impact a person’s ability to meet the responsibilities of their day-to-day life. People suffering from frequent drowsiness often have reduced productivity at work or decreased academic performance in school.

Sleepiness often occurs alongside changes to mood and emotional well-being, and this can negatively impact relationships with family, friends, and co-workers. In addition, significant drowsiness may cause a person to be less active and engaged socially, reducing their connections with others.

A major concern with EDS is the elevated risk of accidents, especially car crashes. EDS is believed to cause a person to be at least 2-3 times more likely to be involved in an auto accident. Drowsy driving has effects similar to drunk driving, but it is much more common far less stigmatized for people to attempt to drive when sleepy. Car crashes can be life-threatening for the driver and others, making EDS of heightened concern for people who find themselves behind the wheel.

Dangerous accidents can occur in many other contexts as well. People who are walking or biking can suffer serious injuries when drowsy, and people in many types of work are at risk of falls or other occupational injuries when suffering from excessive daytime sleepiness.


What Are the Causes of Excessive Daytime Sleepiness?

Excessive daytime sleepiness is not a sleep disorder or health condition in itself. Instead, it is a symptom that is reflective of an underlying cause. Because sleep disruptions can occur as a consequence of many conditions, the potential causes of EDS are numerous.

Insomnia — difficulty falling asleep or staying asleep — is one of the most frequent conditions that is connected to EDS. However, insomnia also has many causes, meaning that insomnia alone usually fails to truly explain the core reason why a person suffers from excessive daytime sleepiness.

Our comprehensive guide about sleep deprivation goes into extensive detail about the potential reasons why a person may suffer from a lack of sleep. Some of the most common causes related to EDS include:

  • Obstructive sleep apnea (OSA): this is a sleep disorder marked by lapses in breathing during the night. Because their sleep is frequently interrupted, people with OSA commonly are burdened with EDS.
  • Narcolepsy: this is a neurological disorder that involves an inability to effectively regulate sleep and wakefulness. People with narcolepsy often feel drowsy and encounter bouts of sudden, extreme sleepiness.
  • Mood and Anxiety Disorders: these mental health conditions, including depression, bipolar disorder, anxiety, and post-traumatic stress disorder (PTSD), can all impact sleep and mood in ways that induce EDS.
  • Delayed Sleep-Wake Phase Disorder: DSWPD is a circadian rhythm sleep disorder in which a person goes to bed late and wakes up late. People who have DSWPD but are forced to wake up early, such as for work, often suffer from drowsiness during the day.
  • Shift Work: people who work a night shift typically have altered sleep schedules that may reduce sleep quantity and quality, resulting in EDS.
  • Jet Lag: traveling across time zones can cause a person’s internal clock to become misaligned with the local time, resulting in sleep problems and daytime sleepiness.
  • Poor Sleep Habits: lack of sleep and consequent EDS can result from poor sleep habits. Examples of these habits could include drinking caffeine late in the day or choosing to stay up late to watch a movie or study instead of dedicating enough time to sleep.
  • Medications: certain types of drugs, especially stimulants that are available both over-the-counter and prescription, can cause a person to suffer from difficulty sleeping and resulting EDS.

This list offers only an introduction to the range of issues that can be related to EDS. In addition, many patients can have multiple contributing factors and may not have just one single cause for feeling tired during the day.


How is Excessive Daytime Sleepiness Diagnosed?

Excessive daytime sleepiness is diagnosed by a doctor who is also directly involved in trying to determine its underlying cause.

The first step in the diagnosis of excessive daytime sleepiness is a health history, including a review of symptoms, and a physical exam. To help the doctor better understand the situation, they may ask a series of questions about how severe their drowsiness is and how frequently it occurs.

A questionnaire may be used to evaluate the patient’s symptoms on the Epworth Sleepiness Scale. This questionnaire is based on a person’s self-reported likelihood of falling asleep in various contexts. A doctor may also ask a patient to keep a sleep journal — also known as a sleep diary or sleep log — for a period of time to get a better understanding of their sleep patterns.

Another test, called the Maintenance of Wakefulness Test (MWT), evaluates whether the patient can stay awake for extended periods and may be useful in determining if someone is at a heightened risk of accidents.

Once it has been established that a patient has EDS, the next step of diagnosis is to attempt to determine the factors contributing to it. This may involve additional testing including blood tests, urine analysis, and/or imaging tests (like computed tomography (CT) or magnetic resonance imaging (MRI)).

More detailed sleep testing may be done at home using special sensors or in a sleep lab where a patient spends the night and is monitored by a sleep technician. This advanced sleep testing is known as polysomnography and is often used to diagnose sleep apnea and other sleep disorders.


How is Excessive Daytime Sleepiness Treated?

Given the multitude of factors that can cause excessive daytime sleepiness, treatment is tailored to fit each patient’s situation. Some of the most common components of treatment are described in the following sections.

Please remember that while our guide is thorough and well-researched, it is not a replacement for medical advice. Always consult your doctor or qualified physician with any questions or concerns you have regarding medical conditions, treatments, and advice.

Treat the Underlying Cause

Because EDS occurs as a secondary effect of other health conditions, a central element of treatment is addressing that underlying condition. Examples could include using positive airway pressure (PAP) devices for sleep apnea, cognitive behavioral therapy (CBT) with or without medications for depression, and altering a patient’s daily medications (or their timing and/or dosage).

In each case, a patient can work closely with their doctor to both diagnose the underlying cause and treat it. As treatment progresses, the patient can continue to check in with their doctor about their level of daytime drowsiness and whether they are seeing an improvement with regard to EDS.

Promote Better Sleep Hygiene

Sleep hygiene is the term used to encompass a person’s sleep-related habits and environment. Some people suffer from EDS because their sleep hygiene is lacking, resulting in inconsistent sleep. In these cases, improving sleep hygiene can go a long way to resolving daytime sleepiness. In people who have an underlying health problem or sleep disorder causing EDS, promoting better sleep hygiene can go hand-in-hand with other therapies.

Sleep hygiene improvements focus on creating healthy practices for preparing for sleep as well as improvements to the sleep environment to make it more conducive to solid rest. Examples of sleep hygiene improvements can include:

  • Having a stable bedtime
  • Creating a set routine for the lead-up to bedtime
  • Avoiding caffeine, alcohol, big meals, or spicy food in the time before bed
  • Eliminating any activities in bed that are not either sleep or sex
  • Stopping the use of mobile phones or other electronic devices for an hour or more before going to bed
  • Practicing meditation or other relaxation techniques
  • Using blackout curtains or a sleep mask to block out exterior light
  • Turning on a white noise machine or using earplugs or headphones to prevent sound-based disturbances
  • Upgrading the sleep surface with a new mattress, mattress topper, pillow, sheets, blanket, or other bedding

Every individual can try out different changes to their sleep hygiene to determine the approach that works best for their needs. More tips for optimizing the setting and routines for sleep can be found in our list of 15 Tips for Better Sleep Hygiene.


Medications can be used in some cases to treat EDS and usually have one of two potential roles. First, medication can be prescribed as part of the therapy for an underlying health condition that is causing EDS. Second, in some cases, prescription stimulant medications may be used to reduce a person’s drowsiness. These drugs are more commonly used when a patient has narcolepsy and/or when EDS persists after trying other treatments.