Fatigue is the most common symptom for people with cancer and the most common side effect of cancer treatment. It 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.

Fatigue usually improves after cancer treatment is finished, but some level of fatigue may continue for months or years. Some people treated for childhood cancer develop fatigue as a late effect during adulthood.


Factors that can cause fatigue or make fatigue worse include:

  • fever
  • anemia
  • infection
  • pain
  • lung, liver, heart or kidney problems
  • electrolyte imbalances
  • poor appetite and nutrition
  • dehydration
  • lack of physical activity
  • sleeping problems
  • hormone imbalance
  • nausea and vomiting
  • stress, anxiety or depression
  • medicines for nausea, pain, anxiety and depression
  • alcohol or recreational drug abuse


Symptoms of fatigue vary depending on their cause and other factors. For example, fatigue may be worse at the beginning and end of a chemotherapy treatment cycle and 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:

  • whole body tiredness or weakness
  • feeling exhausted even after sleep
  • being exhausted mentally or emotionally
  • finding it hard to concentrate, remember or complete tasks
  • confused thinking
  • decreased ability to learn at school or to work, do regular activities or start new things
  • decreased interest in things you enjoy
  • feelings of sadness, frustration or irritability
  • decreased 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.


Both a physical exam and psychological evaluation may be needed to identify possible causes of fatigue and help find out what may be done to treat it. Your doctor will ask you questions about when your fatigue started, how long it has lasted, whether anything makes the fatigue better or worse and how the fatigue affects your daily life.

Your doctor will also look at anything that may be making the fatigue worse. This may include assessing:

  • any pain you are having
  • medicines you are taking
  • your emotions (particularly if you are depressed or anxious)
  • your sleep habits
  • how physically active you are
  • your nutrition
  • any other health conditions

You may need to have the following tests:

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

Managing fatigue

Fatigue can affect everyone differently. For some, fatigue may be more of a nuisance. For others, it interferes greatly with daily life. Your doctor will treat or manage your fatigue based on its possible causes and your individual situation.

Fatigue can be a short-term problem that goes away after treatment ends. It can also continue long after you finish treatment. Follow-up after cancer treatment includes checking for fatigue.

Once your healthcare team knows the cause of your fatigue, they can suggest ways to treat it. Treatment may include nutritional supplements or medicines. If your red blood cell count is low, you may need a blood transfusion.

Some people find it hard to manage fatigue. It can be helpful to keep track of your activity and resting times in a journal or calendar. Make notes of when you are most tired, when you have the most energy and what activities increase fatigue. This can help you find ways to better manage your fatigue. You can also try these tips:

  • Make changes to activities that increase fatigue or try not to do them as often.
  • Plan activities for when you have the most energy.
  • Pick what’s most important to do and do it first. Or do only it.
  • Rest when you need to.
  • Limit stress.
  • Eat well. Talk to a dietitian about healthy eating.
  • Be as physically active as you can be. Ask your doctor about what activities might be good for you.
  • Meditate or try relaxation exercises.
  • Talk to a counsellor to help with your emotions and managing stress.
  • Focus on what you can do and not on what you can’t do.

Expert review and references