FATIGUE Fatigue is feeling tired and a lack of energy. Fatigue is a common experience in patients with cancer. It may be due to the disease itself or to treatment. It may also result from lowered blood counts, lack of sleep, pain and poor appetite. Most people begin to feel tired after a few weeks of radiation therapy treatment. Fatigue generally occurs around the 2nd or 3rd week of radiation therapy and can persist for up to 3 months after completion of therapy. Feelings of weakness or weariness will go away gradually, once your treatment has been completed. During radiation therapy, the body uses a lot of its energy for healing. Stress related to your illness, daily trips for treatment, and the effects of radiation on normal cells may also contribute to tiredness. WHY FATIGUE OCCURS Following radiation treatments, fatigue affects reserve energy used for normal cellular repair. Radiation interferes with normal cell function by causing waste product buildup from cellular destruction; this also can cause fatigue. The routine of going for radiation treatments five times a week can produce fatigue. WHAT TO DO TO HELP FIGHT FATIGUE Try not to do too much, limit your activities and use your leisure time in a restful way. Save energy for doing the things that you feel are most important. Do not feel that you have to do everything! Take several short naps or breaks; these may be more helpful than a long rest period. Sometimes light exercise such as walking may combat fatigue. If you have a full-time job, you may want to try to continue to work your normal schedule. However, some patients prefer to take time off while they are receiving radiation therapy; others work a reduced number of hours. Whether or not you are going to work, it is a good idea to ask family members or friends to help with daily chores, shopping, childcare, housework or driving. Return To Commonly Asked Questions