To add; exercise needs to be thought of as a life critical prescription that needs to be taken every day... if everyone took this prescription AND ate half way decent, (I am now fully believing in the need to eat primarily Alkaline foods at least 60% Alkaline – 40% Acidic; 80 - 20 or better if one is sick) pharmaceutical stock would plummet as there would be little or no need for most prescribed drugs.
Sometimes while I am exercising I imagine I am hunting, searching, picking, and farming for my daily rations of food, if I want to eat for the day, I exercise. Until the last couple hundred years or so, intense physical labor was required by most people in order to eat. It WAS the norm in our evolution (imply social evolution if you are a creationist; the result is the same). If you wanted to get from point A to point B you also had to physically move; there was no sit down and ride, unless in the last 2-3 thousand years or so you were rich enough and/or fortunate enough to have access to a wagon or and/or an ox/horse/mule/donkey and even then, you experienced the effects of passive rebounding AFTER you saddled up or hitched the wagons.