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Cancer Fatigue

What is cancer fatigue?

Cancer fatigue is a condition caused by cancer or cancer treatment in which you feel exhausted or extremely tired. Some people with cancer have extreme fatigue most of the time and are unable to carry out day-to-day tasks. Others feel only very tired. Cancer fatigue may also be called cancer-related fatigue or cancer treatment–related fatigue.

Cancer fatigue is different from fatigue you may have felt in the past. When a healthy person is tired, fatigue is usually caused by activity and goes away after resting or sleeping. However, cancer fatigue is not completely relieved by sleep or rest and may happen after no or minimal activity.

Cancer fatigue is common

Cancer fatigue is one of the most common side effects of cancer treatment. More than 80% of people with cancer experience fatigue while receiving chemotherapy or radiation therapy.

Cancer fatigue can occur at any time

Fatigue can begin at any time—before, during, or after cancer treatment. Sometimes it’s an early symptom of cancer, or it can be brought on by the stress of a cancer diagnosis. Fatigue may worsen gradually as you go through treatment, or it may come on suddenly. Fatigue usually decreases after cancer treatment ends, but some people may still feel fatigue for months or years.

Cancer fatigue can affect many areas of your life

Fatigue can affect not only your daily activities but also your family, work, and social life. Although cancer fatigue can feel overwhelming, your health care team can help you find ways to manage, treat, and cope with fatigue that are tailored to you.

Cancer fatigue symptoms

Female nurse wearing dark green scrubs and pointing at a handheld tablet faces a woman with cancer wearing a beige head wrap and tan cardigan holding her left hand to her chest and smiling calmly.

Feeling very tired, both physically and emotionally, is normal when you have cancer. Your health care team can help identify and treat the causes of fatigue to help you get relief.  

Credit: iStock

Whether and how you experience fatigue depends on factors such as the type of cancer, stage of cancer, cancer treatment(s) you are receiving, and your overall physical and emotional health, nutrition, and sleep patterns.

Symptoms of cancer fatigue include:  

  • having no energy; feeling extremely tired, drained, or lethargic   
  • having difficulty moving; feeling heavy or slow   
  • having difficulty thinking, remembering, or paying attention   
  • having a sense of physical, emotional, and/or mental exhaustion  
  • not feeling rested, even after sleeping  

Causes of cancer fatigue

Cancer itself, cancer treatments, and the side effects of treatment can cause fatigue. Additional sources of fatigue may be stress, changes to your schedule, and other medical conditions.

Fatigue from cancer

Sometimes the source of fatigue in someone with cancer is the cancer itself. Cancer cells use calories and nutrients that your body needs for energy, making you feel fatigued. Cancer can also cause your body to release cytokines, naturally produced substances that help your body to fight infections and cancer but that can cause fatigue when released at high levels. Cachexia, a wasting syndrome that causes muscle and weight loss in some people with cancer, can also lead to fatigue.  

Certain types of cancer are more likely to cause fatigue than others.  

  • Blood cancers such as leukemia, lymphoma, and multiple myeloma affect the bone marrow, making it difficult for your body to produce healthy blood cells. If your red blood cell count is low, your body’s tissues can’t get enough oxygen, resulting in fatigue.  
  • Breast cancer and prostate cancer can affect your hormone levels, which can lead to fatigue.  
  • Gastrointestinal system cancers such as stomach cancer and colorectal cancer can affect the way your body processes and uses food. 

Fatigue from cancer treatments

Many cancer treatments can reduce your energy level. Each treatment may affect fatigue differently, and the treatment’s schedule and dose can influence how fatigued you are and when you feel most tired. Receiving more than one treatment can increase fatigue.

  • Fatigue after surgery. Fatigue is common following surgery while your body is using energy to heal. Pain medicine given after surgery can also cause fatigue. Fatigue from surgery usually improves with time, but when surgery is combined with other treatments, fatigue may last longer.  
  • Fatigue from chemotherapy (chemo fatigue). Chemotherapy destroys healthy cells while treating cancer cells, causing you to feel fatigued. Some people feel the most tired after each chemotherapy treatment, whereas others may have worse fatigue halfway through their course of treatment. Fatigue decreases after chemotherapy is finished, but you may not feel back to normal for a month or more.  
  • Fatigue from radiation therapy. Doctors don’t fully understand why radiation therapy causes fatigue. After radiation therapy begins, fatigue usually increases until midway through the course of treatment then stays about the same until treatment ends.  
  • Fatigue from other treatments. Hormone therapies, immunotherapies, and targeted therapies can all cause fatigue. The timing of when fatigue arises and when it improves can vary depending on the specific treatments and the side effects you experience.

Fatigue from side effects of cancer treatment

Some side effects of cancer treatment can cause or worsen fatigue.   

  • Anemia. Some types of chemotherapy stop bone marrow from making enough new red blood cells, causing anemia (too few red blood cells to carry oxygen to the body’s tissues). Being anemic can lower your energy level.  
  • Appetite loss. Your body’s energy comes from food. If you are not eating well, your body may not get the energy it needs.   
  • Diarrhea. Some cancer treatments cause the body to lose fluid and electrolytes in frequent loose stools. This can lead to dehydration and result in fatigue.  
  • Hot flashes. Some medications change your hormone levels. This can cause hot flashes that may result in night sweats that disrupt your sleep.  
  • Infection. Your body uses energy to fight an infection. You may also have other symptoms with an infection, such as a fever, that can cause fatigue.   
  • Pain. Pain can cause fatigue for many reasons. Lack of sleep from any type of pain will cause fatigue. Medications for treating pain can also make your fatigue worse.  
  • Sleep problems. Many people with cancer have trouble sleeping at night. This can be due to your cancer, medication, or a disrupted sleep pattern, such as sleeping a lot during the day.    
  • Vomiting. Chemotherapy can cause nausea and vomiting before, during, or after it is given. This leads to dehydration from loss of body fluids, which can bring on fatigue.

Fatigue from the emotional impact of cancer

Having a major illness such as cancer can cause you to feel anxious, worried, or fearful. High levels of distress can lead to physical problems such as fatigue, insomnia, and appetite loss. Learn about common emotions experienced by people with cancer and ways to cope.  

Sometimes people experiencing fatigue develop depression. Although it’s normal to feel down at times, depression is more serious. Learn about distress and anxiety as well as symptoms and treatment for depression.

Talking with your doctor about cancer fatigue

Tell your health care team if you feel very weak and tired—especially if you are not able to do your normal activities or are still very tired even after resting or sleeping. 

Your doctor may give you a chart, log, or fatigue diary to help you record your energy level and fatigue each day. This information, together with medical tests, can help your doctor determine the best way for you to manage or cope with fatigue. 

Questions to ask your doctor, nurse, or social worker about cancer fatigue

  • What is most likely causing my fatigue?    
  • Am I at higher risk for fatigue based on the type of cancer I have or the treatment I am receiving?    
  • What can I do to have more energy? Are medical treatments recommended?   
  • Is exercise recommended? What types of movement or other relaxing activities have you found helps people with cancer fatigue?    
  • How much sleep should I get at night? How much rest or sleep may be helpful during the day?    
  • What foods and drinks do you advise? Which should I avoid?    
  • What signs or symptoms should I call you about?

Medical tests used to assess fatigue

Your health care team may check for medical conditions that contribute to fatigue. They’ll perform a physical exam and blood test to check for anemia or infections.  

Your health care team may also ask a series of standard questions about how tired you feel and how it is affecting your daily life. This is called a fatigue assessment. Your health care team will repeat this assessment to see if there is a pattern for when fatigue starts or becomes worse and how to best prevent, manage, or treat it. The same method of measuring fatigue is used at each assessment. This helps show changes in fatigue over time.

Treating cancer fatigue

Your health care team will often treat fatigue by relieving related conditions. They’ll choose a treatment based on your symptoms and whether they know what’s causing the fatigue. When the cause of fatigue is not known, your doctor will treat your symptoms and teach you ways to manage or cope with fatigue.

Medical treatment for cancer-related fatigue

  • Treating anemia. Treatments for anemia may include dietary changes, blood transfusions, or drugs. Learn more about Anemia: Cancer Treatment Side Effect.  
  • Treating pain. Controlling pain can help you feel less tired, but fatigue can also be a side effect of pain medicine. To decrease fatigue, your doctor may recommend switching to a different pain medicine or adjusting the dose or time of day when you take it. Learn more about Pain Management for People with Cancer.
  • Treating depression and anxiety. Sometimes fatigue is worsened by feelings of stress, fear, and hopelessness. Mental health therapists can use cognitive behavioral therapy and talk therapy to help you manage these feelings, which can help decrease fatigue. People with cancer who have a depression diagnosis may also take antidepressant drugs to manage fatigue.
  • Other therapies that may help fatigue. Your health care team may recommend respiratory therapy to help with shortness of breath or other breathing problems that can cause fatigue. They also may recommend physical therapy, which can relieve nerve or muscle problems and help you maintain physical function and strength during and after treatment.
  • Medicines for cancer fatigue. Although there are no standard drug treatments for cancer fatigue, several drugs are being studied for a possible role in treatment.  
    • Psychostimulants are drugs that improve mood and help decrease fatigue and depression. They may increase energy and improve the ability to think and concentrate in some people with cancer, but the FDA has not yet approved psychostimulants for treating fatigue.  
    • Bupropion is an antidepressant that is being studied to treat fatigue in people with cancer with or without depression.  
    • Steroids are being studied in people with advanced cancer. Dexamethasone is a steroid that reduces inflammation but has unwanted side effects.   

Managing cancer fatigue

Eliminating fatigue is not always possible, but there are ways to help lessen or manage cancer-related fatigue. Talk with your health care team about things you can try. Some possibilities include:

Woman with no hair and dark brown eyes sits cross-legged on a yoga mat with her hands in prayer position.

Self-care practices such as yoga, exercise, eating well, and making time to rest can help increase your energy level.

Credit: iStock
  • Rest and sleep.
    • Practice good sleep habits. It is common for people going through treatment for cancer to have changes in their sleep patterns or difficulty sleeping. If you are having problems sleeping, learn how to manage sleep problems in Sleep Disorders.   
    • Plan time to rest. If you are tired, take short naps of less than one hour during the day. Keep in mind that sleeping too much during the day can make it difficult to sleep well at night.   
    • Start with whats most important. Choose activities that are most important to you and do them when you have the most energy. Limit activities that increase your fatigue.
  • Exercise and physical activity. Exercise (including walking) may help people with cancer feel better and have more energy during and after treatment. Choose a physical activity you enjoy. Talk with your health care team or a physical therapist to make an exercise plan that’s right for you.
  • Food and drink. Meet with a registered dietitian to learn about foods and drinks that have the nutrients you need to keep up your energy level. Many people find it easier to eat many small meals throughout the day than three big meals. Drink plenty of water and limit your intake of caffeine and alcohol. Get more tips on eating well in this booklet: Eating Hints: Before, during, and after Cancer Treatment.​​​​​​
  • Mind–body practices. Mind–body practices such as qigong, tai chi, and yoga have been found to reduce fatigue for people with cancer. Many of these practices combine movement, stretching, balance, and controlled breathing with meditation. Relaxation techniques, guided imagery, hypnosis, and acupuncture are other therapies that may help with fatigue. Ask your health care team if there are any programs offered in your community. Learn more about complementary, alternative, and integrative health practices.
  • Supplements. American ginseng in the form of capsules of ground ginger root may be used to treat fatigue. Other dietary supplements, such as coenzyme Q10 and L-carnitine, are also being studied in clinical trials. However, there is no evidence that these supplements reduce cancer fatigue. Learn more about Coenzyme Q10.

Getting support if you have cancer fatigue

If you have fatigue from cancer, you or your caregivers may need help coping. Know that you are not alone and seek support from family and friends and your health care team.

  • Support from family and friends. People you are close to can help with important tasks such as making meals, cleaning, and driving. Get advice on how to ask for help at Changes for the Family.
  • Support from health care providers. If you are having difficulty managing daily activities, your nurse or social worker may help you find services to assist with personal needs such as eating and bathing.
  • Support for caregivers. If you are caring for someone who has fatigue, it is important to know what resources are available to you. Learn more in Support for Caregivers of Cancer Patients.