If you have hypersomnia you likely feel extremely sleepy during the day (different from standard tiredness or fatigue) and want to sleep longer than is normal at night, generally more than ten hours. You may find that sleeping for long lengths of time during the night does not improve your tiredness during the day, and that your sleepiness makes it hard to work, take care of your home, or enjoy the activities you normally do.

Hypersomnia may sound a lot like fatigue, but they are distinct problems. Regular (not chronic or severe) fatigue may respond to increased rest, like a nap during the day. Hypersomnia is unlikely to respond to regular or increased sleep.