More about epinephrine
Studies have shown the body also produces epinephrine during physical activity; the resultant action is the same as described previously.
Even more amazingly, studies indicate that epinephrine plays a part in the activation of natural killer cells (NK, for short). These are a type of white blood cell in our immune system, playing a starring role in attacking “foreign invaders” in the body.
We also learn that NK cells are released into the bloodstream when we exercise, and are a major player in curbing cancer cell growth. (University of Copenhagen: Line Pederson, Manja Idorn, Gitte H. Olofsson, Senior study author, Pernille Hojman et. al.)
And, the process was all started just by exercise!