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Symptom and description

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

If you have hypersomnia, you have difficulty staying awake when you want to and try to. You may sleep 10 hours at night, but still be unable to stay awake during the day. Hypersomnia is different from fatigue. Fatigue is the feeling of being tired, but able to stay awake if you try. If you sleep more than 10 hours at night, or if you are unable to keep from falling asleep during the day after a full night of sleep, you may have hypersomnia.  The most common causes of hypersomnia are your treatment or your mood.

Learning needs

You will need to recognize the symptoms of hypersomnia, how to describe them, and when to report them to your healthcare provider. During a three-week period, you may notice the following symptoms:

  • 10 hours or more of sleep at night

  • Problems staying awake during the day


This sleep problem is hard to prevent if it is due to your treatment.


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 sadness or personal problems, your healthcare provider may either prescribe medicine or refer you to a counselor.

These tips may help you manage hypersomnia: 

  • Exercise every day

  • Maintain a regular sleep regimen, with the same wake-up and bedtime every day

  • Do things you enjoy that require your full attention

  • Avoid foods that make you sleepy

  • Avoid alcohol

Online Medical Reviewer: Gersten, Todd, MD
Online Medical Reviewer: Sather, Rita, RN
Date Last Reviewed: 12/27/2015
© 2013 The StayWell Company, LLC. 800 Township Line Road, Yardley, PA 19067. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare provider's instructions.
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