The idea of "taking exercise" would have seemed ridiculous to our ancestors. Throughout much of history mere survival demanded a level of physical activity that made rest an ultimate luxury. Rarely have people been able to be so sedentary that they needed to exercise apart from their routine of daily living. But in today's industrialized world most people do not have to hunt, fish, or work the fields to get food. We do not have to walk or run long distances to get from one place to another, or chop down trees to build shelters and make fires. Most of us sit while we work, sit while we travel, and sit during our leisure time. The exercise period is a distinctly modern invention.
The news media tell us constantly that physical fitness is not what it should be in our society, that standards of fitness are lax, that children today are not physically fit. The term fitness refers to adaptation. A fit individual is well adapted to his or her environment, able to respond to its changing demands. Many people today who are physically inactive are fit enough for the minimal demands of their comfortable, nonchallenging environments. If you have enough energy and muscle tone to walk up the occasional flight of stairs, mow the grass on weekends, walk the dog, and bend down to open the dishwasher, you may feel you have no reason or need to take up an exercise program. I hear this argument often.
The flaw in it is that our bodies evolved in very demanding environments and are meant to be used. If they are not used, they deteriorate faster than they should. Many of the illnesses that plague our society result from underuse of bodies. Clearly the prevalence of heart and artery disease correlates as much with lack of aerobic exercise as it does with unhealthy diets. Insufficient aerobic activity also predisposes us to musculoskeletal disorders, gastrointestinal problems, nervous and emotional illnesses, and a long list of other ailments.
Read more articles from Dr. Weil on exercise and fitness.