There are now many people who argue that low metabolic rate,

[charlie]

“There are now many people who argue that low metabolic rate, a low body temperature and slow heart beat indicate that you should live a long time: ‘your heart can beat only so many times.’ Most of these people also advocate ‘conditioning exercise,’ and they point out that trained runners tend to have a slow heart rate. (Incidentally, running elevates adrenalin, which causes increased clumping of platelets and accelerated blood clotting. Hypothyroidism – whether pre-existing or induced by running – slows the heart, raises the production of adrenalin, and is strongly associated with heart disease, as well as with high cholesterol.)"