Men who regularly do heart-pounding exercise are less likely to develop cancer, according to a study published in the British Journal of Sports Medicine.
The study found that the key factor in the reduced risk of cancer was a higher rate of oxygen consumption.
A team of researchers from the universities of Kuopio and Oulu in Finland examined the leisure-time physical activity over a 12-month period of 2,560 men between 42 and 61 years old with no history of cancer.
Over an average follow-up period of 16 years, 181 of the subjects died from cancer, mostly of the stomach or intestines, lungs, prostate and brain.
Using an intensity scale for physical exercise that measured "metabolic units" of oxygen consumption, the scientists found that the men who exercised for at least 30 minutes a day were half as likely to get cancer as those who did not.
The sharpest reductions occurred in gastrointenstinal and lung cancers, and held true even when age, alcohol consumption, smoking and weight were taken into account.
"The intensity of leisure-time physical activity should be at least moderate so that beneficial effect ... for reducing overall cancer mortality can be achieved," the researchers conclude.