Fatigue is a feeling of tiredness, weakness, or exhaustion. It is different from drowsiness, which can be relieved with a good night's sleep.
Most people feel fatigue while being treated for cancer. How severe your fatigue is depends on the type of cancer you have, the stage of cancer, and your treatments. Other factors like your general health, diet, and stress level can also add to fatigue.
Fatigue often goes away after your last cancer treatment. For some people though, it can last for months after treatment ends.
What Causes Fatigue
Your fatigue could be caused by one or more factors. Here are ways having cancer can cause fatigue.
Simply having cancer can drain your energy:
- Some cancers release proteins called cytokines that can make you feel fatigued.
- Some tumors can change the way your body uses energy and leave you feeling tired.
Many cancer treatments cause fatigue as a side effect:
- Chemotherapy. You may feel most worn out for a few days after each chemo treatment. Your fatigue may get worse with each treatment. For some people, fatigue is worst about halfway through the full course of chemo.
- Radiation. Fatigue often gets more intense with each radiation treatment until about halfway through the cycle. Then it often levels off and stays about the same until the end of treatment.
- Surgery. Fatigue is common when recovering from any surgery. Having surgery along with other cancer treatments can make fatigue last longer.
- Biologic therapy. Treatments that use vaccines or bacteria to trigger your immune system to fight cancer can cause fatigue.
- Anemia. Some cancer treatments decrease, or kill, red blood cells that carry oxygen from your heart to the rest of your body.
- Poor nutrition. Nausea or lost appetite can make it hard to keep your body fueled. Even if your eating habits do not change, your body may have trouble taking in nutrients during cancer treatment.
- Emotional stress. Having cancer can make you feel anxious, depressed, or distressed. These emotions can drain your energy and motivation.
- Medicines. Many of the medicines for treating pain, depression, insomnia, and nausea can also cause fatigue.
- Sleep problems. Pain, distress, and other cancer side effects can make it hard to get truly rested.
What You Can Do
Talk to your health care provider. Keep track of following details so you can tell your provider about your fatigue.
- When the fatigue started
- Whether your fatigue is getting worse over time
- Times of day when you feel most fatigued
- Anything (activities, people, food, medicine) that seem to make it worse or better
- Whether you have trouble sleeping or feel rested after a full night's sleep
Knowing the level and trigger of your fatigue can help your provider better treat it.
Save your energy. Take steps to organize your home and life. Then you can spend your energy doing what matters most to you.
- Ask friends and family to help you with things like grocery shopping and cooking meals.
- If you have kids, ask a friend or babysitter to take them for an afternoon so you can get some quiet time.
- Put things you use often within easy reach so you do not have to use energy looking for them.
- Save the times of day when you have more energy for doing the things that matter most to you.
- Avoid activities that drain your energy.
- Take time every day to do things that give you energy or help you relax.
Eat well. Make safe nutrition a priority. If you have lost your appetite, eat foods high in calories and protein to keep your energy up.
- Eat small meals throughout the day instead of 2 or 3 big meals
- Drink smoothies and vegetable juice for healthy calories
- Eat olive oil and canola oil with pasta, bread, or in salad dressing
- Drink water between meals to stay hydrated. Aim for 6 to 8 glasses a day
Stay active. Sitting still for too long can make fatigue worse. Some light activity can get your circulation going. You should not exercise to the point of feeling more tired while you are being treated for cancer. But, taking a daily walk with as many breaks as you need can help boost your energy and sleep better.
When to Call the Doctor
Contact your provider if fatigue is making it difficult or impossible for you to manage basic tasks. Call your provider right away if you feel any of these things:
- Unable to get out of bed for 24 hours
- Lose your sense of balance
- Have trouble catching your breath
Cancer - related fatigue
National Cancer Institute website. Fatigue and cancer treatment. www.cancer.gov/about-cancer/treatment/side-effects/fatigue. Updated September 23, 2021. Accessed January 18, 2023.
National Cancer Institute website. Fatigue (PDQ) - health professional version. www.cancer.gov/about-cancer/treatment/side-effects/fatigue/fatigue-hp-pdq. Updated September 1, 2022. Accessed January 18, 2023.
Review Date 10/25/2022
Updated by: Frank D. Brodkey, MD, FCCM, Associate Professor, Section of Pulmonary and Critical Care Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.