The industrial and technological revolutions have made our lives simpler, in terms of what is physically required of us on a daily basis, but they have also made it possible for us to do a whole lot less than we ought to be doing, and we suffer for it. We have become flabby and overweight; our joints and muscles have become stiff from lack of use. We suffer from all sorts of problems related to our lack of physical exercise; it affects us on all levels, causing high blood pressure, increased cholesterol, anxiety, depression, insomnia and the list goes on and on. We know, too, how much better we feel for a bit of exercise. Those “feel-good” hormones lift our spirits, boost self-esteem and improve our overall sense of well-being. It’s a sort of built-in reward system. There’s a reason for that. It’s because we are meant to be active.