How running kills cancer
linked to the release of adrenaline (also called epinephrine), a hormone that is central to the "fight-or-flight" response. Adrenaline production is known to be stimulated by exercise. The researchers say that, the production of adrenaline results in a mobilization of immune cells, specifically one type of immune cell called a Natural Killer (NK) cell, to patrol the body. These NK cells are recruited to the site of the tumor by the protein IL-6, secreted by active muscles. The NK cells can then infiltrate the tumor, slowing or completely preventing its growth. Importantly, the researchers note that injecting the mice with either adrenaline or IL-6 without the exercise proved insufficient to inhibit cancer development, underlining the importance of the effects derived only from regular exercise in the mice.