It is to take care of your cardio-respiratory system. Do not overload your nephrons. Do not overuse your cappilaries, auorta, etc (other vessels and ports on which blood and other metabolic fuel pass).Protect your external pulse points as it may cause a shortage of the pulmonary systemic function on your pulmonary veins. Exercise your cardio-respiratory system through aerobics and any other form of exercise that exercises your bpm and pulse recovery.