Treatment

Hypersomnia During Cancer Treatment

Choose a preferred language


What is hypersomnia?

A good night's sleep is important for your functioning and well-being. But too much sleep can also be a problem. One side effect of cancer and cancer treatment is sleeping too much. This is called hypersomnia. Hypersomnia that's linked to chemotherapy treatment often improves after treatment ends.

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 have trouble staying awake during the day. This sleep problem can be caused by cancer treatments or other medicines.


Causes of hypersomnia

Cancer-related hypersomnia may be caused by:

  • Low levels of red blood cells (anemia).
  • Depression.
  • Anxiety.
  • Pain.
  • Hormone changes, such as hypothyroidism.
  • Certain prescription or over-the-counter medicines. These include chemotherapy, antinausea medicine, sedatives, antihistamines, pain medicines, and antidepressants.


Symptoms of hypersomnia

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


Managing hypersomnia

The treatment for cancer-related hypersomnia depends on the cause. If your sleep problem is due to your treatment, your doctor may want to prescribe medicine to help you stay awake. If your sleep problem is due to depression or stress, your doctor may prescribe medicine or refer you to a counselor or therapist.

These tips may help you manage hypersomnia:

  • Exercise daily in the morning or early afternoon instead of near bedtime.
  • Keep a regular sleep schedule, with the same wake-up and bedtime every day.
  • Do things you enjoy that need your full attention.
  • Don't eat heavy meals or foods that make you sleepy during the day.
  • Don't have alcohol or caffeine.
  • Get bright sunlight during the morning.

Featured in

Date Last Reviewed: 08/31/2025

© 2026 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare provider's instructions.
Heart on hand icon

Cancer is personal

So is the way we treat it.

TALK TO A SPECIALIST
stethoscope icon

Personalized care starts with the right provider

Search by specialty, location, and more.

FIND A DOCTOR
Related Articles
Read article
Oncology
Hormone Therapy for Cancer Treatment

With some cancers, people are given hormone therapy as soon as cancer is diagnosed, before any other treatment. It may shrink a tumor, or it may halt the advance of the disease. In some cancers, such as prostate cancer, hormone therapy helps ease the painful and distressing symptoms of advanced disease.

Read article
Oncology
Radiofrequency Ablation (RFA) of Liver Tumors

Radiofrequency ablation (RFA) is a way to destroy tissue in the body. It can be used as a treatment for cancer. To do it, electricity is sent into a tumor using a needle electrode. The electricity creates heat that kills the cancer cells.

Read article
Oncology
Thyroid Cancer: Radioactive Iodine Therapy

Radioactive iodine therapy uses a form of iodine that sends out radiation to treat thyroid cancer. The goal of this treatment is to target and kill any remaining thyroid cells or thyroid cancer cells anywhere in your body.

Read article
Oncology
Adrenal Cancer: Radiation Therapy

Radiation therapy is not often the main treatment for adrenal cancer. But it may be used after surgery to help keep the cancer from returning. It can also be used to treat other body parts where the tumor has spread.