Cancer treatments can cause fatigue in patients. Fatigue itself can also be a common symptom of some types of cancer. Patients describe feeling weak, worn-out, slow, lack of energy to do their daily activities of living. In some cases, physical fatigue leads to mental fatigue and mood changes. This can make it hard for the patient to pay attention, remember things, and think clearly. Patients treated with chemotherapy usually feel the most fatigue in the days immediately after each treatment. Then the fatigue decreases until the next treatment. Fatigue usually increases with each cycle. For patients receiving radiation therapy, fatigue usually increases until mid-way through the course of treatments and then stays about the same until treatment ends. For many patients, fatigue improves after radiation therapy stops. Biologic therapy can cause symptoms of being tired physically and mentally and not feeling well in general. Consistent exercise, restorative sleep, talk therapy and some supplements make it easier to combat fatigue.