All patients getting cancer treatment should be told to do two and a half hours of physical exercise every week, says a report by Macmillan Cancer Support.

Being advised to rest and take it easy after treatment is an outdated view, the charity says.

Macmillan's report, Move More, says that of the two million cancer survivors in the UK, around 1.6 million are not physically active enough.

Ciaran Devane, chief executive of Macmillan Cancer Support, says exercise plays a big role in the cancer recovery process.

"Cancer patients would be shocked if they knew just how much of a benefit physical activity could have on their recovery and long term health, in some cases reducing their chances of having to go through the gruelling ordeal of treatment all over again.

"It doesn't need to be anything too strenuous, doing the gardening, going for a brisk walk or a swim, all count."

Jane Maher, chief medical officer of Macmillan Cancer Support and a leading clinical oncologist said: "The advice that I would have previously given to one of my patients would have been to 'take it easy'.

"This has now changed significantly because of the recognition that if physical exercise were a drug, it would be hitting the headlines."

Getting active, the report says, can help people fight the effects of cancer and its treatments, including fatigue, stress, weight gain and depression.

“An American research study showed that women with breast cancer who walked at an average pace for 3–5 hours a week, reduced the risk of their cancer coming back and therefore improved their survival. Studies have also shown that exercise may help reduce the risk of bowel cancer coming back.”

How much exercise you undertake will depend on the type of cancer and treatment, the report says.

“It’s important to begin gradually. If you haven’t exercised much before your cancer diagnosis you’ll have to start slowly. Try to set goals that can be achieved at your own pace. A simple activity like walking can be done for a little longer and further each day. Just doing an activity for a few minutes a day can help. Listen to your body and be careful not to overdo it. Your muscles will tell you when you need to stop and rest.”