Why do health clubs have to have those heart machines? Does anyone know how to use them?

Time is critical. AED is the machine you are talking about. In cases in which someone passes out, the machine can save a life if used quickly and its a heart related problem. Most machines have voice instructions and are easy to use. Just put the pads on the person when prompted and the machine can tell you if you need to hit the button to give a shock. Anyone can use the machines if needed.