I know we have to expel energy from our bodies in various ways to maintain homeostasis, but what is producing/generating the radiation to begin with? For example, is it the break down of ATP in cells? I've also heard the heart produces an electromagnetic field, and on that note, how is it that its an electromagnetic field? as in, do we have a changing electric field or a changing magnetic field? edit: oh sorry i finally got my answer in the physics section, didnt think it was going to happen there. https://www.physicsforums.com/showthread.php?t=177156&page=2 mods feel free it remove this if it suits you.