Pumping Iron - when we say Pumping Iron we mean any exercise! We are referring to the Iron in your Blood. We are using the term as a mnemonic device so you remember going from 4 milliliters of blood, to two, three or four hundred milliliters of blood, pumping through your muscles. That's Pumping Iron regardless to wether you have free weights, body weight, swimming, biking... whatever exercise gets your blood going and gives the heart a rest. The question may then be "what are you pumping into your tissues'