Exercise may cut bowel cancer risk by a third

"Exercise has many benefits, including boosting the immune system, decreasing inflammation in the bowel and helping to reduce insulin levels," lead author Dr Kathleen Wolin was quoted as saying by the Daily Mail.

Bowel cancer is the third most common form of the disease, and the second most common among women. There are around 38,600 cases a year in the UK alone.

For the study, the researchers analysed data from 20 existing studies and found people who lead sedentary lifestyles are more likely to have growths.

People who took regular exercise were 16 per cent less likely to develop bowel polyps and 30 per cent less likely to develop large or advanced polyps which are more likely to develop into cancer.

Professor Wolin said: "We`ve long known that an active lifestyle can protect against bowel cancer but this study is the first to look at all the available evidence and show that a reduction in bowel polyps is the most likely explanation for this.

"We hope these results will encourage more people to enjoy the many benefits of regular exercise as part of a healthy lifestyle, including a reduction in bowel cancer risk."

Deborah Alsina, chief executive of Bowel Cancer UK, said: "It is also important that people take part in the screening programme, if eligible, as screening is an effective means of detecting polyps at an early stage.

"These polyps can easily be removed, reducing the risk of bowel cancer developing."

Sara Hiom, director of health information at Cancer Research UK, said: "Evidence shows that keeping active could help to prevent thousands of cases of cancer every year and this study adds weight to evidence showing regular exercise can substantially cut the risk of bowel cancer.

"Getting enough physical activity will also help you keep a healthy weight, which is one of the most important ways of reducing the risk of cancer."

The new research was published in the British Journal of Cancer.