The short answer
Trouble falling or staying asleep, called insomnia, is common during cancer treatment. It can come from treatment side effects, medicines, hospital stays, and stress. As many as half of people have sleep problems during cancer treatment. Good sleep supports your health, and therapies like CBT, relaxation, good bedtime habits, and, sometimes, medicine can help.
Sleep problems, such as trouble falling or staying asleep (insomnia), are common during cancer treatment.
They can be caused by treatment side effects, medicines, long hospital stays, stress, and other factors.
As many as half of all people have sleep-related problems during cancer treatment.
Good sleep supports physical and mental health and may lower the risk of anxiety or depression over time.
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The full explanation.
The simple version
When you have cancer, you may have a hard time sleeping. Trouble falling asleep and/or staying asleep—also called insomnia—is common among people being treated for cancer. In fact, studies show that as many as half of all people have sleep-related problems during treatment.
Tell your health care team if you have trouble sleeping, so you can get the help you need. There are steps that you and your team can take to help you sleep well again.
What causes sleep problems
Sleep problems may be caused by several things at once, including:
- the side effects of treatment
- medicines you are taking
- long hospital stays
- stress
- other factors
Because there can be more than one cause, it helps to talk with your team about what might be affecting your sleep.
Why a good night's sleep matters
Sleeping well is important for your physical and mental health. A good night's sleep may help you:
- think more clearly
- lower your blood pressure
- support your appetite
- strengthen your immune system
Sleep problems that go on for a long time may increase the risk of anxiety or depression. That's one reason it's worth telling your team early.
How sleep problems are checked
Your doctor, or a sleep specialist, can do an assessment to correctly diagnose and treat sleep problems. This may include a polysomnogram—recordings taken during sleep that show brain waves, breathing rate, and other activities such as heart rate. Because sleep problems can change over time, assessments may be repeated from time to time.
Ways to manage sleep problems
- Tell your doctor about problems that interfere with sleep. Getting treatment for problems such as pain, urinary and bladder problems, or diarrhea may help you sleep better.
- Try cognitive behavioral therapy (CBT) and relaxation therapy. A CBT therapist can help you change negative thoughts and beliefs about sleep into positive ones. Muscle relaxation, guided imagery, and self-hypnosis may also help you relax.
- Set good bedtime habits. Go to bed only when sleepy, in a quiet, dark room and a comfortable bed. If you don't fall asleep, get out of bed and return when you're sleepy. Stop watching television or using electronic devices a couple of hours before bed. Don't eat or drink a lot before bedtime. Keep active during the day with regular exercise, but avoid exercising in the few hours before bedtime, since it may make sleep harder.
- Ask about sleep medicine. Your doctor may prescribe sleep medicine for a short period if other strategies don't work. The medicine chosen depends on your specific problem—such as trouble falling asleep or trouble staying asleep—and on other medicines you are taking.
Talking with your team
Prepare for your visit by making a list of questions to ask. You might ask why you're having trouble sleeping, what problems to call about, what steps can help you sleep better, whether a sleep therapist could help, and whether sleep medicine would be advised for you.
When to get help sooner
- Call 911 or go to an emergency department if you are thinking about suicide. The 988 Suicide and Crisis Lifeline also takes calls, texts, and chats at any hour of the day.
- Call your care team the same day if your breathing stops or you choke while asleep, which can be a sign of sleep apnea.
- Call your care team within a day or two if you barely sleep at night, you cannot stay awake during the day, or you think you have restless legs syndrome. Tell them too if low mood is building alongside the sleeplessness.
Words to know
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Common questions
How common are sleep problems during cancer treatment?
Sleep problems are common. Studies show that as many as half of all people have sleep-related problems during treatment for cancer. Trouble falling asleep and staying asleep is also called insomnia.
What causes sleep problems during cancer treatment?
Sleep problems may be caused by the side effects of treatment, medicines you are taking, long hospital stays, stress, and other factors.
Why does good sleep matter?
Sleeping well is important for physical and mental health. A good night's sleep may help you think more clearly, lower your blood pressure, help your appetite, and strengthen your immune system. Sleep problems that last a long time may increase the risk of anxiety or depression.
What can help me sleep better?
Steps include treating problems that interfere with sleep, such as pain or diarrhea; trying cognitive behavioral therapy (CBT) and relaxation techniques; and setting good bedtime habits. Sleep medicine may be prescribed for a short time if other strategies don't work.
What are good bedtime habits?
Go to bed only when sleepy, in a quiet, dark room and a comfortable bed. If you don't fall asleep, get out of bed and return when sleepy. Stop watching TV or using devices a couple of hours before bed, don't eat or drink a lot before bedtime, and avoid exercising in the few hours before sleep.
How are sleep problems assessed?
Your doctor or a sleep specialist can do an assessment, which may include a polysomnogram—recordings taken during sleep that show brain waves, breathing rate, and other activity—to help diagnose and treat the problem. Assessments may be repeated over time.
Questions to ask your doctor
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Last updated: 2026-08-13Next planned review: 2027-01-02
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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