A new study has disclosed that vigorous exercise lowers the chances of developing breast cancer by almost a third.

The defensive effect of strenuous exercise such as scrubbing floors, cleaning windows and dancing was only obvious in women with normal weight, the researchers said.

The other vigorous activities include running, fast jogging, competitive tennis, aerobics, hill cycling, digging, and chopping wood.

The research made by doctors followed the lifestyles and health of 32,269 postmenopausal women for 11 years.

The researchers recorded 1,506 new cases of breast cancer.
 
Lead researcher Dr. Michael Leitzmann from the National Cancer Institute at the US National Institutes of Health said, “Possible mechanisms through which physical activity may protect against breast cancer that are independent of body mass include reduced exposure to growth factors, enhanced immune function, and decreased chronic inflammation, variables that are related both to greater physical activity and to lower breast cancer risk.”

The findings of the study were published in the journal ‘Breast Cancer Research.’

The study discovered that high levels of any activity cuts cancer risk by around 24% in women with normal weight, or a body-mass index of 25 and under. On the other hand, vigorous work out reduced cancer risk by 32%.

Surprisingly, exercise appeared to have no effect on the cancer risk of overweight and obese women. Obesity is known to increase cancer risk in postmenopausal women by up to 30%.