Fatigue is the most common symptom for people with cancer. It is also the most common side effect of cancer treatment. Fatigue is a general lack of energy, tiredness or exhaustion. It is different from the tiredness a person usually feels at the end of the day and it can be a serious problem.

People who have fatigue due to cancer can be exhausted after only small amounts of activity. Sleep or rest doesn't completely relieve this fatigue, and it can interfere with daily life. Coping with cancer can be harder when you have fatigue. Fatigue can also affect your memory and make it hard to think clearly.

Fatigue often improves after cancer treatment is finished, but sometimes it can continue for months or years after you finish treatment. Some people treated for childhood cancer develop fatigue as a late effect when they are adults.

Fatigue for people who have cancer can be called cancer fatigue, cancer-related fatigue or cancer-treatment-related fatigue.


Cancer and its treatments, such as surgery, chemotherapy, radiation therapy and immunotherapy, can cause fatigue.

Different symptoms of cancer or side effects of treatment can also cause fatigue or make it worse. These include anemia, infection, pain, sleeping problems, poor nutrition, physical inactivity, electrolyte or hormone imbalances, stress or depression.

Certain medicines can also cause fatigue or make it worse.


Symptoms of fatigue vary depending on what causes it and other factors. For example, fatigue may be worse at the beginning and end of a chemotherapy treatment cycle. It can also increase throughout the course of radiation treatment.

Fatigue can interfere with all parts of life. It may come and go or be constant. Symptoms of fatigue include:

  • feeling tired or weak all over
  • a feeling of heaviness in the arms or legs
  • feeling exhausted even after sleep
  • being exhausted mentally or emotionally
  • finding it hard to concentrate, remember or complete tasks
  • confused thinking
  • difficulty learning new things
  • difficulty working, doing regular activities or starting new things
  • less interest in things you enjoy
  • feelings of sadness, frustration or irritability
  • lower sexual desire
  • spending more time resting or sleeping

If symptoms get worse or don’t go away, report them to your doctor or healthcare team without waiting for your next scheduled appointment.


Your healthcare team will try to find the cause of your fatigue. This usually involves asking you questions about your fatigue, such as:

  • When did your fatigue start?
  • How long has it lasted?
  • What makes the fatigue better or worse?
  • How does fatigue affect your daily life?

Because fatigue is often caused by more than one problem, your doctor will look at anything that may be making it worse. This may include:

  • any pain you have
  • medicines you are taking
  • your emotions (particularly if you have feelings of depression, anxiety or stress)
  • your sleep habits
  • how physically active you are
  • your nutrition
  • any other changes to your health

You may need to have the following tests:

  • a physical exam
  • blood tests to check your red blood cell count, hormone levels and electrolytes

Some signs of fatigue can be similar to depression. You may have fatigue or depression or both. Your doctor may want you to see a mental health professional to see if depression is part of the problem.

Managing fatigue

Fatigue affects everyone differently. For some, fatigue is just a nuisance. For others, it interferes greatly with daily life. Talk to your healthcare team if you have fatigue. Your doctor will treat or manage your fatigue based on its possible causes and your individual situation.

Treatment may include nutritional supplements or medicines. If your red blood cell count is low, you may need a blood transfusion. If pain is making fatigue worse, your pain medicine may need to be changed. If you have feelings of depression, an antidepressant may help in treating the fatigue.

Often there is no single cause for fatigue but you can manage it by adjusting your behaviour and lifestyle.

Try these tips to help you manage fatigue.

Keep track of fatigue. Keep track of your activity and resting times in a journal or on a calendar. Knowing the level of your fatigue and what triggers it can help the healthcare team suggest ways to treat it. Some things to keep track of are:

  • when the fatigue started
  • whether the fatigue is getting worse over time
  • times of day you are most tired

  • times of day you have the most energy
  • what activities, people, food or medicine make fatigue better or worse
  • whether you have trouble sleeping or feel rested after a full night's sleep

Save your energy for the most important things. Focus on what you can do and not on what you can't do. Plan activities that matter the most for when you have the most energy. For example, if you have the most energy in the morning and you value having a visit with a friend, schedule that for the morning time. Avoid activities that drain your energy. Pick what's important and do it first or make it the only thing you do when your energy is low. It is also possible to change certain activities to make them less draining, such as sitting down to do something rather than standing. Take time to do the things that give you energy or help you relax, such as talking to a friend.

Ask for help. Let people help and ask for help. Give away chores or tasks that you find tiring or hard to do, such as grocery shopping, preparing meals or housecleaning. If you have children, let your friends and family babysit or drive your children to activities, school or daycare.

Eat well. Make good nutrition a priority. Talk to a dietitian about healthy eating. Try to eat foods that are high in calories and protein. Eat small meals throughout the day. Drink smoothies for extra calories. Drink enough water. Find out more about eating well.

Stay active. Be as physically active as you can be. Choose activities that you like to do. This could be taking a cancer-specific exercise class or going for a walk with a friend. Sitting still for too long can make fatigue worse. Movement at any level – easy, moderate or even hard – can boost your energy levels, improve your mood and lessen fatigue. Ask your doctor for a referral to a trained exercise professional to find out more about what movement and activities might be good for you.

Practise good sleep habits. Get a good sleep at night. Try not to sleep too much during the day. Take short naps or rest breaks (30 minutes or less) as needed. A long nap can lower your energy levels and make it harder to sleep at night. Find out more about sleep problems and ways to manage them.

Limit stress. Meditation and breathing or relaxation exercises can also help you to relax. Keep a journal of your feelings and experiences. Talk to a counsellor to help with your emotions and managing stress.

Expert review and references

  • HealthLinkBC. Managing Fatigue (Tiredness). 2020: https://www.healthlinkbc.ca/.
  • My Health Alberta. Weakness and Fatigue. 2020: https://myhealth.alberta.ca/.
  • PDQ® Adult Treatment Editorial Board . Fatigue (PDQ®) – Health Professional Version . Bethesda, MD : National Cancer Institute ; 2021 : https://www.cancer.gov/.
  • PDQ® Adult Treatment Editorial Board . Fatigue (PDQ®) – Patient Version . Bethesda, MD : National Cancer Institute ; 2021 : https://www.cancer.gov/.
  • American Cancer Society. Managing Fatigue or Weakness. 2020: https://www.cancer.org/.
  • US National Library of Medicine. MedlinePlus Medical Encyclopedia: Coping with Cancer - Managing Fatigue. 2020: https://medlineplus.gov/encyclopedia.html.
  • Cohen MZ, White L . Cancer-related distress. Yarbro CH, Wujcki D, Holmes Gobel B, (eds.). Cancer Nursing: Principles and Practice. 8th ed. Burlington, MA: Jones and Bartlett Learning; 2018: 24: 759 - 779.
  • Mitchell SA . Cancer-related fatigue. Yarbro CH, Wujcki D, Holmes Gobel B, (eds.). Cancer Nursing: Principles and Practice. 8th ed. Burlington, MA: Jones and Bartlett Learning; 2018: 28: 883 - 904.

Medical disclaimer

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