In agricultural societies, people are daily physically active in many different ways; but in urban societies, most middle-class adult men and women are physically underactive. Since there is ample evidence that physical health depends on daily physical activity, this indicates an imbalance in town and city life-styles.
A comparison of the death rates between groups that have been able to have daily physical activity with those that have not shows, for example, that in the age group 60 to 64, one percent of the men in the heavy exercise category died during the follow-up year, whereas in the non-exercise group five times as many died.
The shift to sedentary lifestyles is the basis of a major health problem. Although people in industrialized countries tend to consume about 30% fewer calories than in the 1950s, they tend nevertheless to be fatter. Physically demanding jobs have gradually disappeared. Car ownership is growing, so fewer people cycle or walk to work.