People with two of the most common forms of cancer can cut their risk of dying from the disease by as much as 40% simply by walking for a mile a day, Macmillan Cancer Support has claimed.

Those with breast cancer or prostate cancer can reduce their chances of dying if they walk for about 20 minutes a day, the charity says.

Breast cancer sufferers can also lower their risk of the disease recurring if they follow the same regime, as long as the exercise is of moderate intensity – vigorous enough to leave them slightly out of breath.

Bowel cancer patients need to undertake more physical activity to potentially receive similar benefits, however. Doing about six hours a week of moderate intensity exercise can reduce their risk of dying from the disease by up to 50%, according to analysis by Macmillan and the Ramblers, the walking group.

That equates to walking about 18 miles a week in total.

"For cancer patients, physical activity can not only reduce the risk of dying or the cancer coming back, but it can also help to manage some of the devastating side-effects of treatment, such as swelling, fatigue or anxiety," said Ciaran Devane, Macmillan's chief executive.

"We cannot continue to turn a blind eye to what is a very simple and obvious solution. Physical activity is a wonder drug."

The charity is urging health professionals who work with cancer patients to prescribe exercise, especially walking, as part of their efforts to recover and minimise the risk of the disease recurring.

The estimates are based on the Chief Medical Officer's advice that everyone should undertake at least 150 minutes a week of physical activity of moderate intensity and existing evidence about reductions in mortality and recurrence with exercise.

A growing number of research studies internationally have shown how regular exercise, as long as it increases someone's heart rate, can help prevent cancer, or lower the risk of it returning.

Findings in France this month found that postmenopausal women – the group in which breast cancer is most common – who walked or cycled for four hours a week over the previous four years, or undertook two hours of sporting activity, were at lower risk of being diagnosed with the disease compared with women who had not done so.