Reducing risk of breast cancer

On a Dutch blog I found a referal to research done by professor Tony Howell. Googling a bit gives your various articles on this topic which al state the healthy effect of exercise. For example this one also stating the healthy effect of going outdoors. Hmmm, this is something runners combine (if your not runnig on a belt in a sportscentre).

Why is running (and other ecercises) healthy? Of course it helps you to keep you weight in control. And reducing weight is top of the list. Furthermore it has a lowering effect on both the levels of estrogen and insuline which reduces the risks on breast cancer.