We all know that physical activity provides numerous health benefits. A recent study which included 32,269 women examined the relationship between both vigorous and non-vigorous physical activity and its effects on postmenopausal breast cancer risk (Leitzmann MF, et al, 2008).
It was interesting that it was only vigorous activity in lean women that was found to be associated with reduced risk for postmenopausal breast cancer. The same relationship was not found for women with a body mass index of greater than or equal to 25.
Vigorous activity can be a variety of things. Some of the things that researchers mentioned were running, biking uphill and competitive tennis, but there are of course other things you can do as well. You want to keep in mind when you exercise to do it hard enough so that you get your heart rate elevated and you start to breathe heavier.
If you exercise harder, you also need to spend less time exercising to get in shape. That is why top athletes usually incorporate interval training in their routine which means short bursts of high intensity exercise alternating with low intensity or rest.
Leitzmann MF, et al. Prospective study of physical activity and risk of postmenopausal breast cancer. Breast Cancer Res. 2008 Oct 31;10(5):R92.