A good night's sleep is important for your functioning and well-being. But too much sleep can be a problem. One side effect of cancer and cancer treatment is sleeping too much. This is called hypersomnia.

Hypersomnia is different from fatigue. Fatigue is the feeling of being tired, but able to stay awake if you try. If you have hypersomnia, you have trouble staying awake when you want to and try to. You may sleep 10 hours at night, but still can’t stay awake during the day. This sleep problem can be caused by cancer treatments or other medicines.

You may have hypersomnia if you have these symptoms for 3 weeks or more:

• 10 hours or more of sleep at night

• Trouble staying awake during the day despite a full night’s sleep

If your sleep problem is due to your treatment, your healthcare provider may want to prescribe medicine to help you stay awake. If your sleep problem is due to depression or stress, your healthcare provider may prescribe medicine or refer you to a counselor.

These tips may help you manage hypersomnia: 

• Exercise every day.

• Keep regular sleep schedule, with the same wake-up and bedtime every day.

• Do things you enjoy that require your full attention.

• Don't eat foods that tend to make you sleepy.

• Don't drink alcohol.