Hypersomnolence, or excessive daytime sleepiness, can occur even after a person has 7 hours or more of quality sleep. Hypersomnolence categories include acute, subacute, and persistent.

Other terms used to describe hypersomnolence include excessive daytime somnolence and hypersomnia.

Hypersomnolence.Share on Pinterest
Hypersomnolence is when someone is excessively sleepy, regardless of how much sleep they get.

Many people find themselves sleep-deprived or excessively tired at various times in their lives. On the other hand, a person with hypersomnolence can feel the need to sleep even after they have slept well for the recommended number of hours.

Hypersomnolence can be problematic because it affects a person’s abilities at work and school. It can also affect their safety while driving and can be an indicator of an underlying medical disorder.

The symptoms of hypersomnolence usually begin when people are 17 to 24 years old. According to an article in the journal Psychosomatics, the average age of onset is 21.8 years.

Left untreated, hypersomnolence can impact a person’s quality of life.

Share on Pinterest
Symptoms of hypersomnolence include struggling to wake up, falling asleep at random times, and constantly feeling tired.

In people with hypersomnolence, excessive sleepiness is not due to another underlying medical disorder or medication.

The primary symptom of hypersomnolence is excessive sleepiness, even though a person is getting 7 hours of sleep a night. Other symptoms include:

  • falling asleep several times during the day
  • taking naps to combat the sleepiness but not waking up refreshed
  • sleeping more than 9 hours but not feeling rested
  • having difficulty waking up from sleep
  • feeling confused or combative while trying to wake up

Excessive sleeping may cause problems at work, school, or for other daily activities.

Hypersomnolence has three categories: acute, subacute, and persistent.

  • acute hypersomnolence, lasting 1 month or less
  • subacute hypersomnolence, lasting 1 to 3 months
  • persistent hypersomnolence, lasting more than 3 months

Hypersomnolence is similar to another sleep disorder known as narcolepsy in that people experience episodes of sleepiness during the day.

However, people with narcolepsy often describe episodes of sleepiness as sudden sleep “attacks.” In contrast, hypersomnolence episodes tend to come on gradually.

Researchers are still working to identify what interactions in the brain cause hypersomnolance. It is possible that people have an increase in brain chemicals that are known to cause sleepiness. This increase can act much like a sleeping pill.

Although researchers have not yet identified the specific substance or molecule that may be involved in hypersomnolence, they believe it interacts with a substance called y-aminobutyric acid (GABA), which is responsible for promoting sleep in the brain. Sedative medications used in surgery work on the same GABA substance to keep a person asleep during surgery.

Risk factors for a person developing hypersomnolence include:

While these are known risk factors and potential contributors to the condition, some people may have hypersomnolence for no known reason.

Hypersomnolence without a known cause is called idiopathic hypersomnolence, which affects an estimated 0.01 to 0.02 percent of the population.

Hypersomnolence is one of several disorders described in the “sleep-wake disorders” category of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Other conditions in this category include nightmare disorder, restless legs syndrome, and breathing-related sleep disorders.

Doctors often diagnose hypersomnolence by first ruling out other possible causes of the excessive sleepiness.

A doctor will ask questions about a person’s symptoms, which may include:

  • When did you first notice them?
  • Does anything make them worse? Does anything make them better?
  • What other medical conditions are you currently being treated for?
  • What are your sleeping patterns?
  • What is your sleep environment like?

A doctor will also review any medication a person might be taking to help identify if this could be causing the daytime drowsiness.

A doctor may also recommend a sleep study. This involves an overnight stay in a “sleep lab” where a person is hooked up to various monitors, including a pulse oximeter, an electrocardiogram, and a brain wave monitor. This equipment helps the doctor decide if a person’s daytime sleepiness could be due to a sleep disorder, such as obstructive sleep apnea.

If there are no signs of an underlying disorder or medical cause, a doctor may diagnose a person with hypersomnolence.

Share on Pinterest
Establishing a bedtime routine, and limiting distractions before going to sleep, can help to treat hypersomnolence.

Stimulants are most commonly prescribed to treat hypersomnolence. Examples of these medications include:

  • amphetamine
  • methylphenidate
  • modafinil

Additional drugs used to treat hypersomnolence include clonidine, levodopa, bromocriptine, antidepressants, and monoamine oxidase inhibitors (MAOIs).

In addition to medications, a doctor may recommend making changes to a person’s “sleep hygiene” to help them get a good night’s sleep.

Examples of these changes include:

  • Avoiding stimulant substances before bedtime, such as caffeine and nicotine.
  • Drinking alcohol only in moderation. Although alcohol can make a person feel drowsy, drinking it in excess can result in poorer sleep quality.
  • Avoiding foods that cause heartburn or impact digestion. Examples include foods made with high-fat creams, fried foods, spicy meals, citrus fruits, and carbonated drinks.
  • Using visual lighting cues to differentiate between day and night. This can include being exposed to plenty of outdoor light during the day, and making a room darker before going to sleep.
  • Establishing a bedtime routine that a person finds relaxing and helps to signal to their body that it is time for bed. Examples include taking a shower or reading a book.
  • Changing a sleep environment to make it more comfortable. This includes cooling a room to between 60°F-67°F, avoiding light from artificial sources, including cell phones and computers, and sleeping on a comfortable mattress.


With lifestyle changes and medications, doctors consider hypersomnolence to be a very treatable sleep disorder.

A person may also benefit from counseling and cognitive-behavioral therapies to change their sleep habits and learn how to reduce stress when possible.