Regular exercise cuts the risk of developing bowel cancer by a fifth, according to new research.
Experts at Newcastle University found that moderate physical activity causes a cancer-fighting protein to be released into the bloodstream, which can prevent the growth of cancer cells.
They found that regular physical activity reduces the risk by up to 20%.
The study on 16 men aged 50 to 80, all of whom were at risk for bowel cancer, found that 30 minutes of moderate cycling increased the concentration of cancer-fighting cells in the blood.
Dr Sam Orange, lecturer in exercise physiology at Newcastle University, said: ““Our findings are really exciting because they reveal a newly identified mechanism underlying how physical activity reduces bowel cancer risk that is not dependent on weight loss.
He added: “Understanding these mechanisms better could help develop more precise exercise guidelines for cancer prevention.
"It could also help develop drug treatments that mimic some of the health benefits of exercise."