Hypersomnia is when a person feels very sleepy during the day. This could be due to neurological factors or other medical conditions, such as sleep apnea, but sometimes there is no clear cause.

Other names for hypersomnia are excessive daytime sleepiness and hypersomnolence.

People with hypersomnia have difficulty functioning during the day due to sleepiness, which can affect concentration and energy levels.

Here, find out about the types, causes, and symptoms of hypersomnia and how to get help.

Hypersomnia can be idiopathic, primary, or secondary.

Idiopathic hypersomnia is when a person feels exceptionally sleepy for no clear reason.

Primary hypersomnia is when hypersomnia is the main condition. It may be due to neurological causes or occur as a symptom of narcolepsy.

One theory is that, for some people, too much of a certain small molecule is produced in the cerebrospinal fluid. This acts similarly to a sleeping pill or anesthetic. However, more research is needed.

Secondary hypersomnia results from another medical condition, such as:

  • depression
  • multiple sclerosis (MS)
  • nerve damage due to a head trauma
  • drug or alcohol use
  • a tumor
  • damage to the central nervous system
  • medication use
  • sleep apnea

Some of these conditions affect your ability to sleep at night, leading to tiredness during the day.

People with conditions that make them sleepy during the day are most at risk for hypersomnia.

These conditions include:

  • sleep apnea
  • kidney conditions
  • heart conditions
  • nervous system conditions
  • depression
  • low thyroid function
  • encephalitis
  • epilepsy

People who smoke or drink regularly are also at risk of developing hypersomnia. Medications that cause drowsiness can have side effects similar to hypersomnia.

Hypersomnia often starts between the mid teens and early twenties, but it can appear at any time. Symptoms may become more intense at intervals. In females, they may worsen just before menstruation.

Some 10–15% of people find symptoms resolve for no apparent reason, according to the Hypersomnia Foundation.

The main symptom of hypersomnia is constant sleepiness. A person with hypersomnia may sleep more than 11 hours in every 24. They may take naps throughout the day but still feel sleepy.

Other symptoms include:

  • difficulty waking from a long sleep
  • slow thinking and speech
  • difficulty remembering things
  • irritability
  • anxiety
  • low energy
  • hallucinations, in some cases

To diagnose hypersomnia, a doctor will review your symptoms and medical history.

They will likely diagnose hypersomnia if you have experienced the following for at least 3 months:

  • excessive daytime sleepiness
  • an uncontrollable need to sleep
  • long, unrefreshing naps
  • difficulty waking up from sleep in most instances even after typical or longer periods of nighttime sleep

A physical exam can test for alertness.

A doctor may suggest the following to help assess hypersomnia:

  • A sleep diary: You record your sleep and wake times through the night to track sleeping patterns.
  • Epworth sleepiness scale: This scale rates sleepiness to determine the severity of the condition.
  • Multiple sleep latency test: You take a monitored nap during the day while a device measures the types of sleep you experience.
  • Polysomnogram: You stay at a sleep center overnight, and a device monitors brain activity, eye movements, heart rate, oxygen levels, and breathing function.

Treatment will depend on the cause and type of hypersomnia.

Options include:

Stimulant drugs typically used for treating narcolepsy, such as:

  • modafinil (Provigil), a drug to promote wakefulness
  • amphetamines, such as methylphenidate
  • pitolisant (Wakix), another stimulant drug
  • sodium oxybate (Xyrem), which prevents muscle weakness and sleepiness with narcolepsy
  • flumazenil (Romazicon), which reverses the effect of benzodiazepines

Lifestyle changes may help some people either manage their sleep or cope better with hypersomnia.

Tips include:

  • working on a regular sleep schedule, such as waking and sleeping at the same time each day
  • avoiding certain activities, such as eating or working in bed, to improve sleep quality
  • following a diet that is rich in whole foods may help maintain energy levels naturally
  • joining a support group

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Some people with hypersomnia can improve their symptoms with the right lifestyle changes and medication, although some people may never get full relief.

This isn’t a life-threatening condition, but it may impact a person’s quality of life and make it difficult to work, study, and do other everyday activities.

People with hypersomnia should let their doctor know if they receive treatment for another condition, as it can affect the action of some drugs, including anesthesia.

There’s no way to prevent some forms of hypersomnia.

You can reduce the risk of hypersomnia by creating a peaceful sleeping environment and avoiding alcohol and certain medications.

It’s also essential to seek treatment for underlying conditions, as ignoring these may lead to complications.

Hypersomnia can be dangerous if a person drives, uses machinery, or does other work that requires full alertness. It can also affect a person’s studies and social life.

Ignoring hypersomnia may also mean a person is not getting treatment for another condition, such as alcohol use, MS, or depression.

People who sleep most days or for more than an hour a day may have a higher risk of hypertension, stroke, or cardiovascular disease.

What are the signs of hypersomnia?

A person with hypersomnia may feel sleepy, agitated, and low in energy. They may feel slow in thinking and speech and have memory problems. They may nap often but never feel refreshed.

How serious is hypersomnia?

Hypersomnia can be dangerous if it increases the risk of accidents. A person with this condition should check with their doctor if they are safe to drive or use machinery. It can also have a serious impact on a person’s ability to work or study and their quality of life.

How many hours of sleep is hypersomnia?

A person with hypersomnia may sleep more than 11 hours in every 24.

How can I stop hypersomnia?

Options include:

  • seeking treatment for an underlying condition, such as MS
  • using lifestyle strategies, such as avoiding alcohol or establishing a regular sleep-wake routine
  • using medications that a doctor can prescribe

Hypersomnia, sometimes called hypersomnolence, is when a person feels sleepy despite getting enough sleep. It may result from a condition that affects the individual’s ability to sleep, such as depression, or it may occur for no clear reason. In this case, there is likely some neurological cause.

Doctors can use tests to diagnose and assess hypersomnia, and medications are available. Treating an underlying condition may also help relieve it. However, the condition may continue to be challenging for some people.