General Information About Fatigue

Fatigue is the most common side effect of cancer treatment.

Cancer treatments such as chemotherapy, radiation therapy, and biologic therapy can cause fatigue in cancer patients. Fatigue is also a common symptom of some types of cancer. Patients describe fatigue as feeling tired, weak, worn-out, heavy, slow, or that they have no energy or get-up-and-go. Fatigue in cancer patients may be called cancer fatigue, cancer-related fatigue, and cancer treatment-related fatigue.

Fatigue related to cancer is different from fatigue that healthy people feel.

When a healthy person is tired by day-to-day activities, their fatigue can be relieved by sleep and rest. Cancer-related fatigue is different. Cancer patients get tired after less activity than people who do not have cancer. Also, cancer-related fatigue is not completely relieved by sleep and rest and may last for a long time. Fatigue usually decreases after cancer treatment ends, but patients may still feel some fatigue for months or years.

Fatigue can decrease a patient’s quality of life.

Fatigue can affect all areas of life by making the patient too tired to take part in daily activities, relationships, social events, and community activities. Patients may miss work or school, spend less time with friends and family, or spend more time sleeping. In some cases, physical fatigue leads to mental fatigue and mood changes. This can make it hard for the patient to pay attention, remember things, and think clearly. Money may become a problem if the patient needs to take leave from a job or stop working completely. Job loss can lead to the loss of health insurance. All these things can lessen the patient’s quality of life and self-esteem.

Getting help with fatigue may prevent some of these problems and improve quality of life.

Causes of Fatigue in Cancer Patients

Fatigue in cancer patients may have more than one cause.

Doctors do not know all the reasons cancer patients have fatigue. Many conditions may cause fatigue at the same time.

Fatigue in cancer patients may be caused by the following:

• Cancer treatment with chemotherapy, radiation therapy, and some biologic therapies.
• Anemia (a lower than normal number of red blood cells).
• Hormone levels that are too low or too high.
• Trouble breathing or getting enough oxygen.
• Heart trouble.
• Infection.
• Pain.
• Stress.
• Loss of appetite or not getting enough calories and nutrients.
• Dehydration (loss of too much water from the body, such as from severe diarrhea or vomiting).
• Changes in how well the body uses food for energy.
• Loss of weight, muscle, and/or strength.
• Medicines that cause drowsiness.
• Problems getting enough sleep.
• Being less active.
• Other medical conditions.

Fatigue is common in people with advanced cancer who are not receiving cancer treatment.

How cancer treatments cause fatigue is not known.

Doctors are trying to better understand how cancer treatments such as surgery, chemotherapy, and radiation therapy cause fatigue. Some studies show that fatigue is caused by:

• The need for extra energy to repair and heal body tissue damaged by treatment.
• The build-up of toxic substances that are left in the body after cells are killed by cancer treatment.
• The effect of biologic therapy on the immune system.
• Changes in the body’s sleep-wake cycle.

When they begin cancer treatment, many patients are already tired from medical tests, surgery, and the emotional stress of coping with the cancer diagnosis. After treatment begins, fatigue may get worse. Patients who are older, have advanced cancer, or receive more than one type of treatment (for example, both chemotherapy and radiation therapy) are more likely to have long-term fatigue.

Different cancer treatments have different effects on a patient’s energy level. The type and schedule of treatments can affect the amount of fatigue caused by cancer therapy.

Fatigue caused by chemotherapy

Patients treated with chemotherapy usually feel the most fatigue in the days right after each treatment. Then the fatigue decreases until the next treatment. Fatigue usually increases with each cycle. Some studies have shown that patients have the most severe fatigue about mid-way through all the cycles of chemotherapy. Fatigue decreases after chemotherapy is finished, but patients may not feel back to normal until a month or more after the last treatment. Many patients feel fatigued for months or years after treatment ends.

Fatigue during chemotherapy may be increased by the following:

• Pain.
• Depression.
• Anxiety.
• Anemia. Some types of chemotherapy stop the bone marrow from making enough new red blood cells, causing anemia (too few red blood cells to carry oxygen to the body).
• Lack of sleep caused by some anticancer drugs.

Fatigue caused by radiation therapy

Many patients receiving radiation therapy have 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 treatment ends. For many patients, fatigue improves after radiation therapy stops. However, in some patients, fatigue will last months or years after treatment ends. Some patients never have the same amount of energy they had before treatment.

Cancer-related fatigue has been studied in patients with breast cancer and prostate cancer. The amount of fatigue they felt and the time of day the fatigue was worst was different in different patients.

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

• Poor sleep.
• Depression.

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

• Working while receiving radiation therapy.
• Having children at home.
• Depression.
• Anxiety.
• Trouble sleeping.
• Younger age.
• Being underweight.
• Having advanced cancer or other medical conditions.

Fatigue caused by biologic therapy

Biologic therapy often causes flu-like symptoms. These symptoms include being tired physically and mentally, fever, chills, muscle pain, headache, and not feeling well in general. Some patients may also have problems thinking clearly. Fatigue symptoms depend on the type of biologic therapy used.

Fatigue caused by surgery

Fatigue is often a side effect of surgery, but patients usually feel better with time. However, fatigue caused by surgery can be worse when the surgery is combined with other cancer treatments.

Anemia is a common cause of fatigue.

Anemia affects the patient’s energy level and quality of life. Anemia may be caused by the following:

• The cancer.
• Cancer treatments.
• A medical condition not related to the cancer.

The effects of anemia on a patient depend on the following:

• How quickly the anemia occurs.
• The patient’s age.
• The amount of plasma (fluid part of the blood) in the patient’s blood.
• Other medical conditions the patient has.

Side effects related to nutrition may cause or increase fatigue.

The body’s energy comes from food. Fatigue may occur if the body does not take in enough food to give the body the energy it needs. For many patients, the effects of cancer and cancer treatments make it hard to eat well. In people with cancer, three major factors may affect nutrition:

• A change in the way the body is able to use food. A patient may eat the same amount as before having cancer, but the body may not be able to absorb and use all the nutrients from the food. This is caused by the cancer or its treatment.
• A decrease in the amount of food eaten because of low appetite, nausea, vomiting, diarrhea, or a blocked bowel.
• An increase in the amount of energy needed by the body because of a growing tumor, infection, fever, or shortness of breath.

Anxiety and depression are the most common psychological causes of fatigue in cancer patients.

The emotional stress of cancer can cause physical problems, including fatigue. It’s common for cancer patients to have changes in moods and attitudes. Patients may feel anxiety and fear before and after a cancer diagnosis. These feelings may cause fatigue. The effect of the disease on the patient’s physical, mental, social, and financial well-being can increase emotional distress.

About 15% to 25% of patients who have cancer get depressed, which may increase fatigue caused by physical factors. The following are signs of depression:

• Feeling tired mentally and physically.
• Loss of interest in life.
• Problems thinking.
• Loss of sleep.
• Feeling a loss of hope.

Some patients have more fatigue after cancer treatments than others do.

Fatigue may be increased when it is hard for patients to learn and remember.

During and after cancer treatment, patients may find they cannot pay attention for very long and have a hard time thinking, remembering, and understanding. This is called attention fatigue. Sleep helps to relieve attention fatigue, but sleep may not be enough when the fatigue is related to cancer. Taking part in restful activities and spending time outdoors may help relieve attention fatigue.

Not sleeping well may cause fatigue.

Some people with cancer are not able to get enough sleep. The following problems related to sleep may cause fatigue:

• Waking up during the night.
• Not going to sleep at the same time every night.
• Sleeping during the day and less at night.
• Not being active during the day.

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 severe fatigue in both the morning and the evening.

Even in patients who have poor sleep, fixing sleep problems does not always improve fatigue. A lack of sleep may not be the cause of the fatigue. See the PDQ summary on Sleep Disorders for more information.

Medicines other than chemotherapy may add to fatigue.

Patients may take medicines for cancer symptoms, such as pain, or conditions other than the cancer. These medicines may cause the patient to feel sleepy. Opioids, antidepressants, and antihistamines have this side effect. If many of these medicines are taken at the same time, fatigue may be worse.

Taking opioids over time may lower the amount of sex hormones made in the testicles and ovaries. This can lead to fatigue as well as sexual problems and depression.

Assessment of Fatigue

An assessment is done to find out the level of fatigue and how it affects the patient’s daily life.

There is no test to diagnose fatigue, so it is important for the patient to tell family members and the health care team if fatigue is a problem. To assess fatigue, the patient is asked to describe how bad the fatigue is, how it affects daily activities, and what makes the fatigue better or worse. The doctor will look for causes of fatigue that can be treated.

An assessment of fatigue includes a physical exam and blood tests.

The assessment process may include the following:

• Physical exam:

  This is an exam of the body to check general signs of health or anything that seems unusual. The doctor will check for problems such as trouble breathing or loss of muscle strength. The patient’s walking, posture, and joint movements will be checked.

• Rating the level of fatigue:

  The patient is asked to rate the level of fatigue (how bad the fatigue is). There is no standard way to rate fatigue. The doctor may ask the patient to rate the fatigue on a scale from 0 to 10. Other ways to rate fatigue check for how much the fatigue affects the patient’s quality of life.

• A series of questions about the following:
  • When the fatigue started, how long it lasts, and what makes it better or worse.
  • Symptoms or side effects, such as pain, the patient is having from the cancer or the treatments.
  • Medicines being taken.
  • Sleeping and resting habits.
  • Eating habits and changes in appetite or weight.
  • How the fatigue affects daily activities and lifestyle.
  • How the fatigue affects being able to work.
  • Whether the patient has depression, anxiety, or pain.
  • Health habits and past illnesses and treatments.
• Blood tests to check for anemia:

  The most common blood tests to check if the number of red blood cells is normal are:

  • Complete blood count (CBC) with differential: A procedure in which a sample of blood is taken and checked for the following:
    • The number of red blood cells and platelets.
    • The number and type of white blood cells.
    • The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
    • The portion of the blood sample made up of red blood cells.
  • Peripheral blood smear: A procedure in which a sample of blood is checked for the number and kinds of white blood cells, the number of platelets, and changes in the shape of blood cells.
  • Other blood tests may be done to check for other conditions that affect red blood cells. These include a bone marrow aspiration and biopsy or a Coombs’ test. Blood tests to check the levels of vitamin B₁₂, iron, and erythropoietin may also be done.
• Checking for other causes of fatigue that can be treated. See the Causes of Fatigue in Cancer Patients section.

A fatigue assessment is repeated at different times to see if there are patterns of fatigue.

A fatigue assessment is repeated to see if there is a pattern for when fatigue starts or becomes worse. Fatigue may be worse right after a chemotherapy treatment, for example. The same method of measuring fatigue is used at each assessment. This helps show changes in fatigue over time.

Treatments for Fatigue

Fatigue in cancer patients is often treated by relieving related conditions such as anemia and depression.

Treatment of fatigue depends on the symptoms and whether the cause of fatigue is known. When the cause of fatigue is not known, treatment is usually given to relieve symptoms and teach the patient ways to cope with fatigue.

Treatment of anemia

Treating anemia may help decrease fatigue. When known, the cause of the anemia is treated. When the cause is not known, treatment for anemia is supportive care and may include the following:

• Change in diet

  Eating more foods rich in iron and vitamins may be combined with other treatments for anemia.

• Transfusions of red blood cells

  Transfusions work well to treat anemia. Possible side effects of transfusions include an allergic reaction, infection, graft-versus-host disease, immune system changes, and too much iron in the blood.

• Medicine

  Drugs that cause the bone marrow to make more red blood cells may be used to treat anemia-related fatigue in patients receiving chemotherapy. Epoetin alfa and darbepoetin alfa are two of these drugs. This type of drug may shorten survival time, increase the risk of serious heart problems, and cause some tumors to grow faster or recur. The Food and Drug Administration (FDA) has not approved these drugs for the treatment of fatigue. Discuss the risks and benefits of these drugs with your doctor.

Treatment of pain

If pain is making fatigue worse, the patient’s pain medicine may be changed or the dose may be increased. If too much pain medicine is making fatigue worse, the patient’s pain medicine may be changed or the dose may be decreased.

Treatment of depression

Fatigue in patients who have depression may be treated with antidepressant drugs. Psychostimulant drugs may help some patients have more energy and a better mood, and help them think and concentrate. The use of psychostimulants for treating fatigue is still being studied. The FDA has not approved psychostimulants for the treatment of fatigue.

Psychostimulants have side effects, especially with long-term use. Different psychostimulants have different side effects. Patients who have heart problems or who take anticancer drugs that affect the heart may have serious side effects from psychostimulants. These drugs have warnings on the label about their risks. Talk to your 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.

The doctor may prescribe low doses of a psychostimulant to be used for a short time in patients with advanced cancer who have severe fatigue. Talk to your doctor about the risks and benefits of these drugs.

Certain drugs are being studied for fatigue related to cancer.

The following drugs are being studied for fatigue related to cancer:

• Bupropion is an antidepressant that is being studied to treat fatigue in patients with or without depression.
• Dexamethasone is an anti-inflammatory drug being studied in patients with advanced cancer. In one clinical trial, patients who received dexamethasone reported less fatigue than the group that received a placebo. More trials are needed to study the link between inflammation and fatigue.

Certain dietary supplements are being studied for fatigue related to cancer.

The following dietary supplements are being studied for fatigue related to cancer:

• L-carnitine is a supplement that helps the body make energy and lowers inflammation that may be linked to fatigue.
• Ginseng is an herb used to treat fatigue which may be taken in capsules of ground ginseng root. In a clinical trial, cancer patients who were either in treatment or had finished treatment, received either ginseng or placebo. The group receiving ginseng had less fatigue than the placebo group.

Treatment of fatigue may include teaching the patient ways to increase energy and cope with fatigue in daily life.

Exercise

Exercise (including walking) may help people with cancer feel better and have more energy. The effect of exercise on fatigue in cancer patients is being studied. One study reported that breast cancer survivors who took part in enjoyable physical activity had less fatigue and pain and were better able to take part in daily activities. In clinical trials, some patients reported the following benefits from exercise:

• More physical energy.
• Better appetite.
• More able to do the normal activities of daily living.
• Better quality of life.
• More satisfaction with life.
• A greater sense of well-being.
• More able to meet the demands of cancer and cancer treatment.

Moderate activity for 3 to 5 hours a week may help cancer-related fatigue. You are more likely to follow an exercise plan if you choose a type of exercise that you enjoy. The health care team can help you plan 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 cancer treatment.

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

A schedule of activity and rest

Changes in daily routine make the body use more energy. A regular routine can improve sleep and help the patient have more energy to be active during the day. A program of regular times for activity and rest help to make the most of a patient’s energy. A health care professional can help patients plan an exercise program and decide which activities are the most important to them.

The following sleep habits may help decrease fatigue:

• Lie in bed for sleep only.
• Take naps for no longer than one hour.
• Avoid noise (like television and radio) during sleep.

Cancer patients should not try to do too much. Health professionals have information about support services to help with daily activities and responsibilities.

Talk therapy

Therapists use talk therapy (counseling) to treat certain emotional or behavioral disorders. This kind of therapy helps patients change how they think and feel about certain things. Talk therapy may help decrease a cancer patient’s fatigue by working on problems related to cancer that make fatigue worse, such as:

• Stress from coping with cancer.
• Fear that the cancer may come back.
• Feeling hopeless about fatigue.
• Not enough social support.
• A pattern of sleep and activity that changes from day to day.

Self-care for fatigue

Learning about the risk of cancer-related fatigue and how to reduce fatigue may help you cope with it better and improve quality of life. For example, some patients in treatment worry that having fatigue means the treatment is not working. Anxiety over this can make fatigue even worse. Some patients may feel that reporting fatigue is complaining. Knowing that fatigue is a normal side effect that should be reported and treated may make it easier to manage.

Working with the health care team to learn about the following may help patients cope with fatigue:

• How to cope with fatigue as a normal side effect of treatment.
• The possible medical causes of fatigue such as not enough fluids, electrolyte imbalance, breathing problems, or anemia.
• How patterns of rest and activity affect fatigue.
• How to schedule important daily activities during times of less fatigue, and give up less important activities.
• The kinds of activities that may help you feel more alert (walking, gardening, bird-watching).
• The difference between fatigue and depression.
• How to avoid or change situations that cause stress.
• How to avoid or change activities that cause fatigue.
• How to change your surroundings to help decrease fatigue.
• Exercise programs that are right for you and decrease fatigue.
• The importance of eating enough food and drinking enough fluids.
• Physical therapy for patients who have nerve problems or muscle weakness.
• Respiratory therapy for patients who have trouble breathing.
• How to tell if treatments for fatigue are working.

Fatigue After Cancer Treatment Ends

Fatigue continues to be a problem for many cancer survivors long after treatment ends and the cancer is gone. Studies show that some patients continue to have moderate-to-severe fatigue years after treatment. Long-term therapies such as tamoxifen can also cause fatigue. In children who were treated for brain tumors and cured, fatigue may continue after treatment.

The causes of fatigue after treatment ends are different than the causes of fatigue during treatment. Treating fatigue after treatment ends also may be different from treating it during cancer therapy.

Since fatigue may greatly affect the quality of life for cancer survivors, long-term follow-up care is important.

Current Clinical Trials

Use our clinical trial search to find NCI-supported cancer clinical trials that are accepting patients. You can search for trials based on the type of cancer, the age of the patient, and where the trials are being done. General information about clinical trials is also available.

About This PDQ Summary

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This PDQ cancer information summary has current information about the causes and treatment of fatigue. It is meant to inform and help patients, families, and caregivers. It does not give formal guidelines or recommendations for making decisions about health care.

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A clinical trial is a study to answer a scientific question, such as whether one treatment is better than another. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients. During treatment clinical trials, information is collected about the effects of a new treatment and how well it works. If a clinical trial shows that a new treatment is better than one currently being used, the new treatment may become “standard.” Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.

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PDQ® Supportive and Palliative Care Editorial Board. PDQ Fatigue. Bethesda, MD: National Cancer Institute. Updated <MM/DD/YYYY>. Available at: https://www.cancer.gov/about-cancer/treatment/side-effects/fatigue/fatigue-pdq. Accessed <MM/DD/YYYY>. [PMID: 26389259]

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Last Revised: 2019-05-15

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