Idiopathic hypersomnia is a rare, chronic [sleep disorder](https://www.masterclass.com/articles/sleep-disorders-explained) that causes excessive daytime sleepiness (EDS). People with hypersomnia may notice excessive sleepiness during adolescence or young adulthood, and the disorder usually progresses over time before peaking and stabilizing. Common symptoms of hypersomnia include feeling tired after napping or waking after a full night’s sleep, and falling asleep while performing routine tasks, such as working, driving, or having a meal or conversation. This excessive daytime sleepiness may be constant or recurring, but in either case, it can adversely affect the ability to tackle the responsibilities of daily life. 

The International Classification of Sleep Disorders (ICSD) categorizes idiopathic hypersomnolence as a central disorder of hypersomnolence or a condition marked by excessive sleepiness. Other hypersomnolence disorders include [narcolepsy](https://www.masterclass.com/articles/narcolepsy-explained) type 1(with cataplexy) and narcolepsy type 1(without cataplexy). Other sleep-related conditions, like circadian disturbances, insufficient sleep syndrome, and obstructive [sleep apnea](https://www.masterclass.com/articles/sleep-apnea-guide), may also cause excessive drowsiness. However, the sleepiness associated with those conditions can often be relieved by getting extra sleep, unlike idiopathic hypersomnia.

The symptoms of idiopathic hypersomnia are all characterized by excessive sleepiness. They include:

1. __Brain fog__: Also known as clouding of consciousness, brain fog is a common symptom of hypersomnia that creates focus-related issues and confusion. It may be difficult to form a thought, speak, remember, or understand ideas with brain fog.
2. __Chronic excessive daytime sleepiness__: One of the major symptoms of hypersomnia is fatigue. People with the disorder may feel persistently sleepy and exhausted throughout the day and may need to [nap](https://www.masterclass.com/articles/napping-tips) throughout the day. But even after long periods of nocturnal sleep and daytime naps, they may still feel unrested. This state of constant and excessive sleepiness can make it challenging to engage in everyday activities.
3. __Mental and physical reactions__: Hypersomnia can also trigger mental and physical reactions like cold hands and feet, headaches or dizziness after waking up, excessive sweating, and feeling faint or hungry. People with the disorder may hallucinate and experience [sleep paralysis](https://www.masterclass.com/articles/sleep-paralysis-explained).
4. __Sleep inertia__: Also known as sleep drunkenness, sleep inertia involves feeling groggy and disoriented after transitioning from sleep to wakefulness. This feeling can last anywhere from 15 minutes to several hours and makes tasks that require even basic motor skills challenging.
5. __Short sleep latency__: Sleep latency refers to how long it takes you to sleep once you are in bed and ready to turn in for the night. People with hypersomnia may experience a shorter latency, falling asleep in an unusually short amount of time (less than eight minutes) than average sleepers. 

If you are experiencing symptoms of idiopathic hypersomnia, consult a sleep specialist for medical advice. They can help you determine possible treatment options, which may include polysomnography ([sleep study](https://www.masterclass.com/articles/sleep-study-guide)), a multiple sleep latency test, testing hypocretin levels, keeping a [sleep diary](https://www.masterclass.com/articles/sleep-diary-guide), or disorder-specific medications. 

Saw some of the best darn logs of your life with a [MasterClass Annual Membership](https://www.masterclass.com) and exclusive instructional videos from Dr. Matthew Walker, the author of *Why We Sleep* and the founder-director of the Center for Human Sleep Science at the University of California, Berkeley. Between Matthew’s tips for optimal snoozing and info on discovering your body’s ideal rhythms, you’ll be sleeping more deeply in no time.  
Idiopathic hypersomnia is a rare condition that causes extreme and often unexpected sleepiness. 


Idiopathic hypersomnia is a rare condition that causes extreme and often unexpected sleepiness. 


Idiopathic Hypersomnia: 5 Symptoms of the Sleep Disorder

Idiopathic hypersomnia is a rare, chronic <a href='https://www.masterclass.com/articles/sleep-disorders-explained' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/sleep-disorders-explained","linkCopy":"sleep disorder","category":null}'>sleep disorder</a> that causes excessive daytime sleepiness (EDS). People with hypersomnia may notice excessive sleepiness during adolescence or young adulthood, and the disorder usually progresses over time before peaking and stabilizing. Common symptoms of hypersomnia include feeling tired after napping or waking after a full night’s sleep, and falling asleep while performing routine tasks, such as working, driving, or having a meal or conversation. This excessive daytime sleepiness may be constant or recurring, but in either case, it can adversely affect the ability to tackle the responsibilities of daily life. The International Classification of Sleep Disorders (ICSD) categorizes idiopathic hypersomnolence as a central disorder of hypersomnolence or a condition marked by excessive sleepiness. Other hypersomnolence disorders include <a href='https://www.masterclass.com/articles/narcolepsy-explained' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/narcolepsy-explained","linkCopy":"narcolepsy","category":null}'>narcolepsy</a> type 1(with cataplexy) and narcolepsy type 1(without cataplexy). Other sleep-related conditions, like circadian disturbances, insufficient sleep syndrome, and obstructive <a href='https://www.masterclass.com/articles/sleep-apnea-guide' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/sleep-apnea-guide","linkCopy":"sleep apnea","category":null}'>sleep apnea</a>, may also cause excessive drowsiness. However, the sleepiness associated with those conditions can often be relieved by getting extra sleep, unlike idiopathic hypersomnia.

What Is Idiopathic Hypersomnia?

The symptoms of idiopathic hypersomnia are all characterized by excessive sleepiness. They include:<ol class="mc-m-4"><li class="mc-my-4"> 1. Brain fog: Also known as clouding of consciousness, brain fog is a common symptom of hypersomnia that creates focus-related issues and confusion. It may be difficult to form a thought, speak, remember, or understand ideas with brain fog. </li><li class="mc-my-4"> 2. Chronic excessive daytime sleepiness: One of the major symptoms of hypersomnia is fatigue. People with the disorder may feel persistently sleepy and exhausted throughout the day and may need to <a href='https://www.masterclass.com/articles/napping-tips' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/napping-tips","linkCopy":"nap","category":null}'>nap</a> throughout the day. But even after long periods of nocturnal sleep and daytime naps, they may still feel unrested. This state of constant and excessive sleepiness can make it challenging to engage in everyday activities. </li><li class="mc-my-4"> 3. Mental and physical reactions: Hypersomnia can also trigger mental and physical reactions like cold hands and feet, headaches or dizziness after waking up, excessive sweating, and feeling faint or hungry. People with the disorder may hallucinate and experience <a href='https://www.masterclass.com/articles/sleep-paralysis-explained' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/sleep-paralysis-explained","linkCopy":"sleep paralysis","category":null}'>sleep paralysis</a>. </li><li class="mc-my-4"> 4. Sleep inertia: Also known as sleep drunkenness, sleep inertia involves feeling groggy and disoriented after transitioning from sleep to wakefulness. This feeling can last anywhere from 15 minutes to several hours and makes tasks that require even basic motor skills challenging. </li><li class="mc-my-4"> 5. Short sleep latency: Sleep latency refers to how long it takes you to sleep once you are in bed and ready to turn in for the night. People with hypersomnia may experience a shorter latency, falling asleep in an unusually short amount of time (less than eight minutes) than average sleepers. </li></ol>

5 Common Symptoms of Idiopathic Hypersomnia

If you are experiencing symptoms of idiopathic hypersomnia, consult a sleep specialist for medical advice. They can help you determine possible treatment options, which may include polysomnography (<a href='https://www.masterclass.com/articles/sleep-study-guide' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/sleep-study-guide","linkCopy":"sleep study","category":null}'>sleep study</a>), a multiple sleep latency test, testing hypocretin levels, keeping a <a href='https://www.masterclass.com/articles/sleep-diary-guide' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/sleep-diary-guide","linkCopy":"sleep diary","category":null}'>sleep diary</a>, or disorder-specific medications.

Treatment of Idiopathic Hypersomnia

Saw some of the best darn logs of your life with a <a href='https://www.masterclass.com' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com","linkCopy":"MasterClass Annual Membership","category":null}'>MasterClass Annual Membership</a> and exclusive instructional videos from Dr. Matthew Walker, the author of Why We Sleep and the founder-director of the Center for Human Sleep Science at the University of California, Berkeley. Between Matthew’s tips for optimal snoozing and info on discovering your body’s ideal rhythms, you’ll be sleeping more deeply in no time.

Want to Learn More About Catching Those Elusive Zs?

Idiopathic hypersomnia is a rare condition that causes extreme and often unexpected sleepiness.