It’s well-known that exercise reduces the risk of cancer and can help patients ward off tumors if they already have cancer, but now we may understand why this is. Researchers at Copenhagen University found that exercise produces adrenalin, which increases the production of natural killer cells. Still, an injection of adrenalin wouldn’t be enough to help someone who wasn’t exercising fight cancer. The researchers found that another chemical called interleukin-6 increases with exercise and that the combination of that and adrenalin helps to fend off cancer. This is valuable information, with researchers now looking at the potential of using adrenalin and interleukin-6 as anti-tumor drugs. In any case, we now have one more reason to exercise.