Research has long shown that those who exercise are less likely to get cancer. But a new study is finally helping experts understand why high levels of physical activity inhibit the development and growth of cancer in the body. 

The study, published in medical journal Cell Metabolism by a group of Danish researchers, highlighted the effect of exercise on the development of cancer tumors in mice. They did this by implanting cancer cells into all of the mice, but only giving half of the rodents access to a running wheel. 

After a month, the mice that had been using the wheel were 60 percent less likely to have developed cancer tumors, and those that had developed the disease typically had less dramatic symptoms than the sedentary group.