Exercise prevents heart attacks when you have excessive calories, you get adequate sleep and do not sleep outside in the winter, you have a dry place to stand a

Exercise prevents heart attacks when you have excessive calories, you get adequate sleep and do not sleep outside in the winter, you have a dry place to stand and are not out in the rain and so on. Exercise leads to muscle loss when the fat reserves are depleted and calorie intake is limited. Anyway there are ways to falsify or verify that hypothesis, but it needs some resources, not much but still, it needs time and subjects to test the hypothesis on. So for the foreseeable future, it will stay as it is, a hypothesis.