+ -Text Size

Feeling Tired vs. Cancer-Related Fatigue

If you’re fighting cancer, chances are you’re also fighting fatigue. Fatigue is being tired – physically, mentally, and emotionally. It’s the most common side effect of cancer treatment, and it often hits without warning. Everyday activities – talking on the phone, shopping for groceries, even lifting a fork to eat – can be overwhelming tasks.

Cancer-related fatigue is different

Research suggests that most people getting cancer treatment have fatigue. Cancer-related fatigue is very different from everyday fatigue. Cancer-related fatigue is worse. It lasts longer and sleep doesn’t make it better: it’s unpredictable. And many people describe it as overwhelming, affecting every part of their lives.

Cancer-related fatigue can last from months to years, and continues after treatment ends, too. Many people with cancer say fatigue is the most distressing side effect of cancer and its treatment.

For people getting chemotherapy in cycles, fatigue often gets worse in the first few days and then gets better until the next treatment, when the pattern begins again. For those getting radiation, fatigue usually gets worse as the treatment goes on.

Left untreated, cancer-related fatigue can upset the patient’s quality of life. It can affect daily routines, self-care, recreation, and relationships.

Some signs of cancer-related fatigue are:

  • Prolonged, extreme tiredness after an activity
  • Feeling weak, tired, weary, or exhausted even after sleeping
  • Arms and legs feel heavy and hard to move
  • Too tired to complete normal daily activities
  • Having trouble concentrating, thinking clearly, or remembering
  • Feeling frustrated, irritable, and upset about the fatigue and its effects
  • Not taking part in normal day-to-day activities
  • Putting less energy into personal appearance
  • Spending more time in bed or sleeping

Causes of cancer-related fatigue

It’s not fully understood what causes cancer-related fatigue. It may be the cancer and/or the cancer treatment. Problems like low levels of certain blood cells, sleep problems, stress, pain, eating too little, lack of exercise, and other factors are also thought to be linked to this kind of fatigue.

When there are no obvious physical causes for a patient or survivor’s excessive fatigue, doctors might want to run tests to check for other medical problems. Sometimes medical causes can be found and treated. If no treatable medical cause is found, there are practical ways to manage and minimize cancer-related fatigue, including good sleep habits, approved physical activities, and smart use of your time and energy. Doctors are also researching medicines to help people manage fatigue.

It’s important for you to tell someone on your health care team about fatigue and any other unpleasant side effects you’re having. This way they can monitor and treat them, both during cancer treatment and afterward when some problems can linger. You may need to come up with different ways to do things, decide what you can give up, set priorities, and get help so you can better manage them.

Fatigue or depression?

Some signs of fatigue look a lot like those of depression, and it’s easy to confuse them. Depression involves an inability to feel pleasure – people who are depressed feel sad or unworthy. They may give up hope. You can have fatigue and not be depressed, although some people have both fatigue and depression.

Sometimes it may be hard to find a label for what you’re feeling. Your doctor might want you to see a mental health professional to get another opinion on whether depression is part of the problem. If it is, treatment can help.

Try to tell your doctor exactly how you feel and how it affects the things you do. People with fatigue may describe feeling tired, weak, exhausted, weary, worn-out, or slow. They often have no energy and can’t focus. They may feel sad, irritable, or frustrated.

Only you know if you have fatigue and how it’s changing your ability to enjoy life. Talk to your health care team so you can find ways to feel better.

To learn more

7 Ways to Manage Cancer-Related Fatigue

Fatigue in People With Cancer

Anxiety, Fear, and Depression

Distress in People With Cancer


Jacobsen PB, Donovan KA, Weitzner MA. Distinguishing fatigue and depression in patients with cancer. Semin Clin Neuropsychiatry. 2003;8(4):229-240.

Koornstra RH, Peters M, Donofrio S, van den Borne B, de Jong FA. Management of fatigue in patients with cancer -- a practical overview. Cancer Treat Rev. 2014;40(6):791-799.

National Cancer Institute. Fatigue PDQ (Health Professional Version), modified 8/28/14. Accessed at www.cancer.gov/cancertopics/pdq/supportivecare/fatigue/HealthProfessional on October 7, 2014.

Trudel-Fitzgerald C, Savard J, Ivers H. Which symptoms come first? Exploration of temporal relationships between cancer-related symptoms over an 18-month period. Ann Behav Med. 2013;45(3):329-337.

Mitchell SA, Berger AM. Fatigue. In Cancer: Principles & Practice of Oncology, 9th Ed. DeVita VT Jr, Lawrence TS, Rosenberg SA (Eds). Philadelphia, Lippincott, Williams & Wilkins. 2011: 2387-2392.

Last Medical Review: 10/09/2014
Last Revised: 10/22/2014