Fatigue (PDQ®)

As a National Cancer Institute (NCI)-designated Comprehensive Cancer Center, a core part of our mission is to educate patients and the community about cancer. The following summary is trusted information from the NCI.


This patient summary on fatigue is adapted from a summary written for health professionals by cancer experts. This and other credible information about cancer treatment, screening, prevention, supportive care, and ongoing clinical trials is available from the National Cancer Institute. Fatigue is one of the most common complaints of people diagnosed with cancer and cancer survivors. This brief summary describes fatigue, its causes and treatment.

This summary is about fatigue in adults with cancer.


Fatigue occurs in 14% to 96% of people with cancer, especially those receiving treatment for their cancer. Fatigue is complex, and has biological, psychological, and behavioral causes. Fatigue is difficult to describe and people with cancer may express it in different ways, such as saying they feel tired, weak, exhausted, weary, worn-out, heavy, or slow. Health professionals may use terms such as asthenia, fatigue, lassitude, prostration, exercise intolerance, lack of energy, and weakness to describe fatigue.

Fatigue can be described as a condition that causes distress and decreased ability to function due to a lack of energy. Specific symptoms may be physical, psychological, or emotional. To be treated effectively, fatigue related to cancer and cancer treatment needs to be distinguished from other kinds of fatigue.

Fatigue may be acute or chronic. Acute fatigue is normal tiredness with occasional symptoms that begin quickly and last for a short time. Rest may alleviate fatigue and allow a return to a normal level of functioning in a healthy individual. Chronic fatigue syndrome describes prolonged debilitating fatigue that may persist or relapse, and is not related to cancer. Fatigue related to cancer is called chronic because it lasts over a period of time and is not completely relieved by sleep and rest. Chronic fatigue diagnosed in patients with cancer may be called "cancer fatigue", "cancer-related fatigue", or "cancer treatment-related fatigue". Although many treatment- and disease-related factors may cause fatigue, the exact process of fatigue in people with cancer is not known.

Fatigue can become a very important issue in the life of a person with cancer. It may affect how the person feels about him- or herself, his or her daily activities, family care, and relationships with others, and whether he or she continues with cancer treatment. Patients receiving some cancer treatments may miss work or school, withdraw from friends, need more sleep, and, in some cases, may not be able to think clearly or perform any physical activities because of fatigue. Finances can become difficult if people with fatigue need to take disability leave or stop working completely. Job loss may result in the loss of health insurance or the inability to get medical care. Understanding fatigue and its causes is important in determining effective treatment and in helping people with cancer cope with fatigue. Tests that measure the level of fatigue have been developed.

How long fatigue lasts and how much fatigue the patient feels depends on the type and schedule of cancer treatment. For example, patients treated with cycles of chemotherapy usually have the most fatigue in the days following treatment, then less fatigue until the next treatment. Patients treated with external-beam radiation therapy usually have more fatigue as their treatment continues. It is likely that most patients beginning cancer treatment already feel fatigued following diagnostic tests, surgery, and the emotional distress of coping with a cancer diagnosis.


Most of the causes of fatigue in patients with cancer are poorly understood, and patients are likely to be coping with many possible causes of fatigue at the same time. Fatigue commonly is an indicator of disease progression and is frequently one of the first symptoms of cancer in both children and adults. For example, parents of a child diagnosed with acute lymphocytic leukemia or non-Hodgkin lymphoma frequently seek medical care because of the child's extreme fatigue. Tumors can cause fatigue directly or indirectly by spreading to the bone marrow, causing anemia, and by forming toxic substances in the body that interfere with normal cell functions. People who are having problems breathing, another symptom of some cancers, may also experience fatigue.

Fatigue can occur for many reasons. The extreme stress that people with cancer experience over a long period of time can cause them to use more energy, leading to fatigue. However, there may be other reasons that patients with cancer suffer from fatigue. The central nervous system (the brain and spinal cord) may be affected by the cancer or the cancer therapy (especially biological therapy) and cause fatigue. Medication to treat pain, depression, vomiting, seizures, and other problems related to cancer may also cause fatigue. Tumor necrosis factor (TNF), a protein made mainly by white blood cells, can cause necrosis (death) of some types of tumor cells and may be given to a patient as a cancer treatment. TNF may cause the loss of protein stores in muscles, making the body work harder to perform normal functions and causing fatigue. There are many chemical, physical, and behavioral factors that are thought to cause fatigue.

Factors Related to Fatigue

It is not always possible to determine the factors that cause fatigue in patients with cancer. Possible factors include the following:

Cancer treatment

Fatigue is a common symptom following radiation therapy or chemotherapy. Fatigue may also be a side effect of biologic response modifier therapy, a type of treatment to boost or restore the ability of the immune system to fight cancer, infections, and other diseases. It may be caused by anemia, or the collection of toxic substances produced by cells. In the case of radiation, it may be caused by the increased energy needed to repair damaged skin tissue.

Several factors have been linked with fatigue caused by chemotherapy. Some people may respond to the diagnosis and treatment of cancer with mood changes and disrupted sleep patterns. Nausea, vomiting, chronic pain, and weight loss can also cause fatigue.

Studies have reported that patients have the most severe fatigue around mid-way through all the cycles of chemotherapy. Fatigue decreases after chemotherapy is finished, but patients often don't feel back to normal even 30 days after the last treatment.

Fatigue during cancer treatment may be increased by the following factors:

Many patients undergoing radiation therapy report fatigue that keeps them from being as active as they want to be. After radiation therapy begins, fatigue usually increases until mid-way through the course of treatments and then stays about the same until treatments end. Fatigue usually lessens after the therapy is completed, but some fatigue may last for months or years following treatment. Patients who are older, have advanced disease, or receive combination therapy (for example, chemotherapy plus radiation therapy) are at a higher risk for developing long-term fatigue.

In men with prostate cancer, fatigue was increased by having the following symptoms before radiation therapy started:

  • Poor sleep.
  • Depression.
  • Anxiety.
  • Pain.

In women with breast cancer, fatigue was increased by the following:

  • Working while undergoing radiation therapy.
  • Having children at home.
  • Depression.
  • Anxiety.
  • Poor sleep.
  • Younger age.
  • Being underweight.
  • Having advanced cancer or other medical conditions.

Biological therapy frequently causes fatigue. In this setting, fatigue is one of a group of side effects known as flu-like syndrome. This syndrome also includes fever, chills, muscle pain, headache, and a sense of generally not feeling well. Some patients may also experience problems with their ability to think clearly. The type of biological therapy used may determine the type and pattern of fatigue experienced.

Many people with cancer undergo surgery for diagnosis or treatment. Fatigue is a problem following surgery, but fatigue from surgery improves with time. It can be made worse, however, when combined with the fatigue caused by other cancer treatments.


Anemia may be a major factor in cancer-related fatigue and quality of life in people with cancer. Anemia may be caused by the cancer, cancer treatment, or may be related to other medical causes.

Nutrition factors

Fatigue often occurs when the body needs more energy than the amount being supplied from the patient's diet. In people with cancer, 3 major factors may be involved: a change in the body's ability to process food normally, an increased need by the body for energy (due to tumor growth, infection, fever, or problems with breathing), and a decrease in the amount of food eaten (due to lack of appetite, nausea, vomiting, diarrhea, or bowel obstruction).

Psychological factors

The moods, beliefs, attitudes, and reactions to stress of people with cancer can also contribute to the development of fatigue. Anxiety and depression are the most common psychological disorders that cause fatigue.

Depression may be a disabling illness that affects approximately 15% to 25% of people who have cancer. When patients experience depression (loss of interest, difficulty concentrating, mental and physical tiredness, and feelings of hopelessness), the fatigue from physical causes can become worse and last longer than usual, even after the physical causes are gone. Anxiety and fear associated with a cancer diagnosis, as well as its impact on a person's physical, mental, social, and financial well-being are sources of emotional stress. Distress from being diagnosed with cancer may be all that is needed to trigger fatigue. Some patients report having more fatigue after cancer treatments than others do. Studies have found that patients who worry about or expect fatigue before, during, or after treatment may be more likely to report having fatigue. (Refer to the PDQ summaries on Depression and Adjustment to Cancer: Anxiety and Distress for more information.)

Mental ability factors

Decreased attention span and difficulty understanding and thinking are often associated with fatigue. Attention problems are common during and after cancer treatment. Attention may be restored by activities that encourage rest. Sleep is also necessary for relieving attention problems but it is not always enough.

Sleep disorders and inactivity

Disrupted sleep, poor sleep habits, less sleep at night, sleeping a lot during the day, or no activity during the day may contribute to cancer-related fatigue. Patients who are less active during the daytime and awaken frequently during the night report higher levels of cancer-related fatigue.

Poor sleep affects people in different ways. For example, the time of day that fatigue is worse may be different. Some patients who have trouble sleeping may feel more fatigue in the morning. Others may have periods of severe fatigue in both the morning and the evening.

Even in patients who have poor sleep, correcting sleep problems does not always decrease fatigue. A lack of sleep may not be what is causing the fatigue.


Medications other than those used in chemotherapy may also contribute to fatigue. Opioids used in treating cancer-related pain often cause drowsiness, the extent of which may vary depending on the individual. Taking opioids over time may lower the amount of sex hormones made in the testes in men and the ovaries in women. This can lead to fatigue as well as sexual dysfunction and depression. Other types of medications such as tricyclic antidepressants and antihistamines may also produce the side effect of drowsiness. Taking several medications may compound fatigue symptoms.


To determine the cause and best treatment for fatigue, the person's fatigue pattern must be determined, and all of the factors causing the fatigue must be identified. The doctor will look for causes of fatigue that can be treated. The following factors must be included:

  1. Fatigue pattern, including how and when it started, how long it has lasted, and its severity, plus any factors that make fatigue worse or better.
  2. Type and degree of disease and of treatment-related symptoms and/or side effects.
  3. Treatment history.
  4. Current medications.
  5. Sleep and/or rest patterns and relaxation habits.
  6. Eating habits and appetite or weight changes.
  7. Effects of fatigue on activities of daily living and lifestyle.
  8. Psychological profile, including an evaluation for depression.
  9. Complete physical examination that includes evaluation of walking patterns, posture, and joint movements.
  10. How well the patient is able to follow the recommended treatment.
  11. Job performance.
  12. Financial resources.
  13. Other factors (for example, anemia, breathing problems, decreased muscle strength).

Underlying factors that contribute to fatigue should be evaluated and treated when possible. Contributing factors include anemia, depression, anxiety, pain, dehydration, nutritional deficiencies, sedating medications, and therapies that may have poorly tolerated side effects. Patients should tell their doctors when they are experiencing fatigue and ask for information about fatigue related to underlying causes and treatment side effects.

Anemia evaluation

There are different kinds of anemia. A medical history, a physical examination, and blood tests may be used to determine the kind and extent of anemia that a person may have. In people with cancer there may be several causes.


Most of the treatments for fatigue in cancer patients are for treating symptoms and providing emotional support because the causes of fatigue that are specifically related to cancer have not been determined. Some of these symptom-related treatments may include adjusting the dosages of pain medications, administering red blood cell transfusions or blood cell growth factors, diet supplementation with iron and vitamins, and antidepressants or psychostimulants.

Psychostimulant drugs

Fatigue in patients who have depression may be treated with antidepressant or psychostimulant drugs. Psychostimulants may help some patients have more energy and a better mood, and may help them think and concentrate. The use of psychostimulants for treating fatigue is still under study. The doctor may prescribe low doses of a psychostimulant to be used for a short time in advanced cancer patients with severe fatigue.

Psychostimulants have side effects, especially with long-term use. Different psychostimulants have different side effects. Patients who have heart problems or are taking anticancer drugs that affect the heart may have serious side effects from psychostimulants. These drugs have boxed warnings on the label about their risks. It is important to talk with a doctor about the effects these drugs may have and use them only under a doctor's care. Some of the possible side effects include the following:

  • Trouble sleeping.
  • Euphoria (feelings of extreme happiness).
  • Headache.
  • Nausea.
  • Anxiety.
  • Mood changes.
  • Loss of appetite.
  • Nightmares.
  • Paranoia (feelings of fear and distrust of other people).
  • Serious heart problems.

Treatment for anemia

Treatment for fatigue that is related to anemia may include red blood cell transfusions. Transfusions are an effective treatment for anemia; however possible side effects include infection, immediate transfusion reaction, graft-versus-host disease, and changes in immunity.

Treatment for anemia-related fatigue in patients undergoing chemotherapy may also include drugs, such as epoetin alfa, that cause the bone marrow to make more red blood cells. This type of drug may shorten survival time, increase the risk of serious heart problems, and cause some tumors to grow faster. Patients should discuss the risks and benefits of these drugs with their doctors.


Moderate activity for 3 to 5 hours a week may help cancer-related fatigue. Choosing a type of exercise that will be enjoyed makes an exercise plan more likely to be followed. The health care team can help with planning the best time and place for exercise and how often to exercise. Patients may need to start with light activity for short periods of time and build up to more exercise little by little. Studies have shown that exercise can be safely done during and after active cancer treatment.

People with cancer who exercise may have more physical energy, improved appetite, improved ability to function, improved quality of life, improved outlook, improved sense of well-being, enhanced sense of commitment, and improved ability to meet the challenges of cancer and cancer treatment. Findings from a study of breast cancer survivors suggest that patients may be able to lessen fatigue and pain and function better in daily activities if they take part in moderate to vigorous recreational sports after cancer treatment.

Exercise may also help patients with advanced cancer, even those in hospice care. More benefit may result when family members are involved with the patient in the physical therapy program.

Mind and body exercises such as qigong, tai chi, and yoga may also help relieve fatigue. These exercises combine activities like movement, stretching, balance, and controlled breathing with mental exercise such as meditation.

Cognitive Behavior Therapy

Cognitive behavior therapy (CBT) is a method used by therapists to treat a variety of psychological disorders. CBT aims to change a patient's awareness (the cognitive) in order to change the way he acts (the behavior). CBT sessions may be helpful in decreasing a patient's fatigue following cancer treatment by focusing on factors such as:

  • Stress from coping with the experience of having cancer.
  • Fear that the cancer may come back.
  • Abnormal attitudes about fatigue.
  • Irregular sleep or activity patterns.
  • Lack of social support.

Activity and rest

Any changes in daily routine require the body to use more energy. People with cancer should set priorities and keep a reasonable schedule. Health professionals can help patients by providing information about support services to help with daily activities and responsibilities. An activity and rest program can be developed with a health care professional to make the most of a patient's energy. Practicing sleep habits such as not lying down at times other than for sleep, taking short naps no longer than one hour, and limiting distracting noise (TV, radio) during sleep may improve sleep and allow more activity during the day.

Patient education

Treating chronic fatigue in patients with cancer means accepting the condition and learning how to cope with it. People with cancer may find that fatigue becomes a chronic disability. Although fatigue is frequently an expected, temporary side effect of treatment, other factors may cause it to continue. Learning the facts about cancer-related fatigue may help patients cope with it better and improve their quality of life. For example, some patients in active treatment worry that fatigue is a sign that the treatment is not working. They may feel that reporting fatigue is complaining. Anxiety over this can make fatigue even worse. Knowing that fatigue is a normal side effect that should be reported and treated may make it easier to manage.

Since fatigue is the most common symptom in people receiving outpatient chemotherapy, patients should learn ways to manage the fatigue. Patients should be taught the following:

  • The difference between fatigue and depression
  • Possible medical causes of fatigue (not enough fluids, electrolyte imbalance, breathing problems, anemia)
  • To observe their rest and activity patterns during the day and over time
  • To engage in attention-restoring activities (walking, gardening, bird-watching)
  • To recognize fatigue that is a side effect of certain therapies
  • To participate in exercise programs that are realistic
  • To identify activities which cause fatigue and develop ways to avoid or modify those activities
  • To identify environmental or activity changes that may help decrease fatigue
  • The importance of eating enough food and drinking enough fluids
  • Physical therapy may help with nerve or muscle weakness
  • Respiratory therapy may help with breathing problems
  • To schedule important daily activities during times of less fatigue, and cancel unimportant activities that cause stress
  • To avoid or change a situation that causes stress
  • To observe whether treatments being used to help fatigue are working

Current Clinical Trials

Check NCI's list of cancer clinical trials for U.S. supportive and palliative care trials about fatigue and anemia that are now accepting participants. The list of trials can be further narrowed by location, drug, intervention, and other criteria.

General information about clinical trials is also available from the NCI Web site.

Posttreatment Considerations

This section is for patients who have had no cancer treatment for at least 6 months. The causes of fatigue are different for patients who are receiving therapy compared to those who have completed therapy. Also, the treatment for fatigue may be different for patients who are no longer receiving treatment for cancer.

Fatigue in people who have completed treatment for cancer and who are considered to be disease-free is a different condition than the fatigue experienced by patients receiving therapy. Fatigue may significantly affect the quality of life of cancer survivors. Studies show that some patients continue to have moderate-to-severe fatigue for up to 18 years after bone marrow transplantation. Long-term therapies such as tamoxifen can also cause fatigue. Fatigue can cause poor school performance years later in children who were treated for brain tumors and cured. Long-term follow-up care is important for patients after cancer therapy. Physical causes should be ruled out when trying to determine the cause of fatigue in cancer survivors.

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Clinical Trials