It's a good thing too, because when it quits, you quit (unless you happen to be on the operating table getting a transplant). So we exercise and try to eat right to keep our hearts fit and keep the plumbing open to ease its job of moving blood around, bringing oxygen to our brain and tissues.
There is another heart that we talk about sometimes, the heart of our mind. The inner sanctum of our will. That place that Jesus talks about so much. The thought strikes me: is my spiritual heart as resilient as my physical heart? How much spiritual exercise am I getting, and what sorts of spiritual food am I taking in?