"I’ve noticed a trend. The ones who are most successful seem to be the ones who value their physical and mental health."
This could be skewed. I'd imagine entrepreneurs who are already successful have the mental peace to order their life and make time for these things. Those without success will be overly concerned with making something work and figure they can deal with physical and mental health when they have achieved success. So the statistics or things you are reading may look like there is a causal relationship between exercise, sleep --> success, but it is really success --> exercise, sleep.