Exercise is a "wonder drug" for cancer survivors and may even prevent the disease returning, according to a new report.
Macmillan Cancer Support , a British agency that lobbies for better support for cancer sufferers and their families, said physical activity should be "prescribed" by doctors after "hard evidence" showed it can significantly help recovery and prevent other long-term illnesses.
Rather than patients being told to "rest up" as in the past, doctors must encourage people to get moving as soon as they feel able.
A review of more than 60 studies for the charity found people undergoing treatment for cancer -- as well as survivors -- could benefit from exercise.
During treatment, being active did not worsen people's fatigue and had positive effects on mood and well-being, the study said. Once treatment has finished, exercise can reduce the impact of side-effects, such as swelling around the arm, anxiety, depression, fatigue, and impaired mobility.
"Long term, it is an effective way to help recover physical function, manage fatigue, improve quality of life and mental health, and control body weight," the report, 'Move More', said.
The research also showed exercise had an impact on preventing recurrence of a few specific cancers.
Women with breast cancer who exercise for 150 minutes a week at moderate intensity have more than a 40pc lower risk of dying and recurrence of the disease compared with women who are active for less than one hour a week.
Results of two studies on bowel cancer also show the risk of dying or the disease coming back is cut by about 50pc in patients doing six hours a week of moderate intensity exercise.
Furthermore, prostate cancer patients have about a 30pc lower risk of dying from the disease and a 57pc lower rate of disease progression if they do three hours of moderate intensity exercise a week.
The authors of the study said medical guidelines of 150 minutes of moderate activity a week were appropriate for most cancer survivors if built up gradually. Moderate exercise includes very brisk walking, heavy cleaning, such as washing windows, vacuuming and mopping, cycling and badminton.
Macmillan estimates that about three-quarters of cancer sufferers are not physically active for 150 minutes a week.
The survey of more than 400 health professionals in Britain also found most GPs and oncology nurses were unaware of the guidelines on exercise -- just 41pc and 42pc answered correctly.
More than half (56pc) of GPs, practice nurses, oncologists and cancer nurses also did not speak to their patients about the possible benefits of exercise, or only spoke to a few of them.