Since the dawn of civilization mankind has had to deal with the ravages of sloth. The wealthy man, having hired others to work his fields and carry his bundles, do his laundry and run his errands, finds himself short of breath and getting pains in his chest. Nature designed man to meet the struggle for existence, to be able to walk through his days in search of food and water, to climb trees and cliffs for a snatch of food. The last thing nature foresaw was a life of sloth. But that is what an increasing number of mankind lives.
How can the physically idle stay physically fit, and in their busy lives how can they maximize the time they spend on physical fitness. This has been extensively studied by humans concerned about rising rates of obesity and heart disease, especially as they might find themselves in the danger zone. Late in the game, they throw themselves into an exercise program, as though every ounce of sweat will work a pound of cure, but most often the damage has been done and such programs can even bring on the demise of the fanatic. The best course of action is gradual during any acclimation period. If one has not been walking, much less running - then walk, don't run. If one has not been lifting weights, then start with the 20 pound weights. Stop when you are short of breath, as tomorrow you will find you have more stamina. Give your body a chance to catch up. Take a day off now and then from the routine, you're not in a race, you know.
Just as civilization brought the demons of sloth onto mankind, the demons of plenty have left their mark. Rich food, the type eaten only on occasion by early man, is on the platter every day, and the richer the better. Pass the butter, please. High fiber foods, normally the staple in early man, may be absent altogether. Early man ate frequently, shat frequently due to his high fiber diet, and drank all he could hold when encountering clean water. Protein feasts were rare, and on those occasions early man ate nothing but the protein until this was gone or he was chased from the find or kill. The healthiest diet is one that takes mankind's beginnings into consideration.
Probably the most important physical fitness advice we can give to the human animal caught in the rigors of civilization's incessant demands is not to worry. If a matter is not in your control, put it from your mind. What will be, will be, and your stress diseases will not change this one way or the other.