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Fatigue is a common side effect, and there is a good chance that you will feel some level of fatigue from radiation therapy.

What it is

Fatigue from radiation therapy can range from a mild to an extreme feeling of being tired. Many people describe fatigue as feeling weak, weary, worn out, heavy, or slow.


Why it occurs

Fatigue can happen for many reasons. These include:

  • Anemia
  • Anxiety
  • Depression
  • Infection
  • Lack of activity
  • Medicines


Fatigue can also come from the effort of going to radiation therapy each day or from stress. Most of the time, you will not know why you feel fatigue.


How long it lasts

When you first feel fatigue depends on a few factors, which include your age, health, level of activity, and how you felt before radiation therapy started.


Fatigue can last from 6 weeks to 12 months after your last radiation therapy session. Some people may always feel fatigue and, even after radiation therapy is over, will not have as much energy as they did before.


Ways to manage it

  • Try to sleep at least 8 hours each night. This may be more sleep than you needed before radiation therapy. One way to sleep better at night is to be active during the day. For example, you could go for walks, do yoga, or ride a bike. Another way to sleep better at night is to relax before going to bed. You might read a book, work on a jigsaw puzzle, listen to music, or do other calming hobbies.
  • Plan time to rest. You may need to nap during the day. Many people say that it helps to rest for just 10 to 15 minutes. If you do nap, try to sleep for less than 1 hour at a time.
  • Try not to do too much. With fatigue, you may not have enough energy to do all the things you want to do. Stay active, but choose the activities that are most important to you. For example, you might go to work but not do housework, or watch your children's sports events but not go out to dinner.
  • Exercise. Most people feel better when they get some exercise each day. Go for a 15- to 30-minute walk or do stretches or yoga. Talk with your doctor or nurse about how much exercise you can do while having radiation therapy.
  • Plan a work schedule that is right for you. Fatigue may affect the amount of energy you have for your job. You may feel well enough to work your full schedule, or you may need to work less - maybe just a few hours a day or a few days each week. You may want to talk with your boss about ways to work from home so you do not have to commute. And you may want to think about going on medical leave while you have radiation therapy.
  • Plan a radiation therapy schedule that makes sense for you. You may want to schedule your radiation therapy around your work or family schedule. For example, you might want to have radiation therapy in the morning so you can go to work in the afternoon.
  • Let others help you at home. Check with your insurance company to see whether it covers home care services. You can also ask family members and friends to help when you feel fatigue. Home care staff, family members, and friends can assist with household chores, running errands, or driving you to and from radiation therapy visits. They might also help by cooking meals for you to eat now or freeze for later.
  • Learn from others who have cancer. People who have cancer can help each other by sharing ways to manage fatigue. One way to meet other people with cancer is by joining a support group - either in person or online. Talk with your doctor or nurse to learn more about support groups.
  • Talk with your doctor or nurse. If you have trouble dealing with fatigue, your doctor may prescribe medicine (called psychostimulants) that can help decrease fatigue, give you a sense of well-being, and increase your appetite. Your doctor may also suggest treatments if you have anemia, depression, or are not able to sleep at night.