The report recommends that all patients getting cancer treatment should do two-and-a-half hours of physical exercise every week. It doesn't have to be anything strenuous. It could be gardening, going for a brisk walk, and swimming.
Macmillan Cancer Support looked at 60 studies and surveyed more than 400 health professionals.
Researchers say getting active can help people overcome the effects of cancer and its treatments, such as fatigue and weight gain. They also say regular exercise could help reduce the risk of cancer coming back.