Cancer-Related Fatigue

Medically Reviewed by Murtaza Cassoobhoy, MD on May 23, 2023
Written by WebMD Editorial Contributors
5 min read

Fatigue is a common side effect of cancer and its treatments, but there are steps you can take to combat it.

If you have cancer, keep a diary for one week to identify the time of day when you are either most fatigued or have the most energy. Note what you think may be contributing factors.

Be alert to your personal warning signs of fatigue. Fatigue symptoms may include:

  • Tired eyes or legs
  • Whole-body tiredness
  • Stiff shoulders
  • Decreased energy or lack of energy
  • Inability to concentrate
  • Weakness or malaise
  • Boredom or lack of motivation
  • Sleepiness
  • Increased irritability or impatience
  • Nervousness or anxiety

There are several ways to conserve your energy during your cancer fight. Here are some suggestions:

Plan ahead and organize your work.

  • Change storage of items to reduce trips or reaching.
  • Delegate tasks when needed.
  • Combine activities and simplify details.

Schedule rests.

  • Balance periods of rest and work.
  • Rest before you become fatigued -- frequent, short rests can help.

Pace yourself.

  • A moderate pace is better than rushing through activities.
  • Reduce sudden or prolonged strains.
  • Alternate sitting and standing.
  • When feeling overwhelmed or fatigued, practice focused breathing to help you relax.

Practice proper body mechanics.

  • When sitting, use a chair with good back support. Sit up with your back straight and your shoulders back.
  • Adjust the level of your work -- work without bending over.
  • When bending to lift something, bend your knees and use your leg muscles to lift, not your back. Do not bend forward at the waist with your knees straight.
  • Carry several small loads instead of one large one, or use a cart.

Limit work that requires reaching over your head and increases muscle tension.

  • Use long-handled tools.
  • Store items lower.

Identify effects of your environment.

  • Avoid temperature extremes.
  • Eliminate smoke or harmful fumes.
  • Avoid long, hot showers or baths.

Prioritize your activities.

  • Decide what activities are important to you, and what could be delegated.
  • Use your energy on important tasks.

Cancer-related fatigue is often made worse if you are not eating enough or if you are not eating the right foods. Maintaining good nutrition can help you feel better and have more energy. You may not always be able to eat perfectly, but the following are some goals:

  • Meet your basic calorie needs Ask your doctor or other member of your cancer treatment team how many calories you need each day.
  • Eat plenty of protein. Protein rebuilds and repairs damaged (and normally aging) body tissue. It’s generally recommended that you get between 10 and 35 percent of your total daily calories from protein, but this depends on many factors. If you have had surgery or other treatments for cancer, you may need more protein to help your body heal and fight off infection. Ask your doctor or dietitian about your individual nutrition goals. The best sources of protein include foods from the dairy group (8 oz. milk = 8 grams protein) and meats (meat, fish, or poultry = 7 grams of protein per ounce).
  • Drink plenty of fluids. A minimum of 8 cups of fluid per day will help prevent dehydration. (That's 64 ounces, 2 quarts, or 1 half-gallon). In hot, dry climates you may need to increase your fluid intake. Ask a member of your health care team about your specific fluid needs. Fluids can include juice, milk, broth, milkshakes, gelatin, and other beverages. Of course, water is fine, too. Keep in mind that you'll need more fluids if you have treatment side effects such as vomiting or diarrhea.
  • Make sure you are getting enough vitamins. Talk to your doctor about taking a vitamin supplement if you are not sure you are getting enough nutrients. A recommended supplement would be a multivitamin that provides at least 100% of the recommended daily allowances (RDA) for most nutrients. Note: Vitamin supplements do not provide calories, which are essential for energy production. So vitamins cannot substitute for adequate food intake. As with all medications, you should check with your doctors or nurses before taking vitamins or other supplements.
  • Make an appointment with a dietitian. A registered dietitian can provide suggestions for dealing with eating problems that may be interfering with proper nutrition (such as early feeling of fullness, nausea, swallowing difficulty, or taste changes). A dietitian can also suggest ways to maximize calories and include more nutrients in smaller amounts of food (such as powdered milk, instant breakfast drinks, and other commercial supplements or food additives). 

Decreased physical activity, which may be the result of cancer or cancer treatment, can lead to tiredness and lack of energy. Scientists have found that even healthy athletes forced to spend extended periods in bed or sitting in chairs develop feelings of anxiety, depression, weakness, fatigue, and nausea.

Regular, moderate exercise can often decrease these feelings, help you stay active, and increase your energy. Even during cancer therapy, it is often possible to continue exercising.

Here are some guidelines to keep in mind.

  • Check with your doctor before beginning an exercise program.
  • A good exercise program starts slowly, allowing your body time to adjust.
  • Keep a regular exercise schedule. Exercise at least three times a week.
  • The right kind of exercise never makes you feel sore, stiff, or exhausted. If you experience soreness, stiffness, exhaustion, or feel out of breath as a result of your exercise, you are overdoing it.
  • Most exercises are safe, as long as you exercise with caution and don't overdo it.  Among the safest and most productive activities are swimming, brisk walking, yoga, indoor stationary cycling, and low impact aerobics (taught by a certified instructor). These activities carry little risk of injury and benefit your entire body if done correctly.

Although cancer-related fatigue is a common, and often expected, side effect of cancer and its treatments, you should mention your concerns to your doctors. There are times when fatigue may be a clue to an underlying medical problem. Other times, there may be treatments to help control some of the causes of fatigue.

Finally, there may be suggestions that are more specific to your situation that would help in combating your fatigue.

Warning Signs

Be sure to let your doctor or nurse know right away if you have:

  • Shortness of breath with minimal exertion
  • Uncontrolled pain
  • Inability to control side effects from treatments (such as nausea, vomiting, diarrhea, or loss of appetite)
  • Uncontrollable anxiety or nervousness
  • Depression