But it must be understood, that unless designed otherwise, i.e. unless the Units of Analysis are chosen from all people, most studies are generalizable only for a much narrower population of the people w/in a nation, region, city, etc.
exercising - the activity of exerting your muscles in various ways to keep fit; the doctor recommended regular exercise; he did some exercising; the physical exertion required by his work kept him fit. exercise, physical exercise, physical exertion, workout.
The definition of exercise is to use something or to engage in physical activity done in order to stay healthy or to cause someone else to engage in physical activity in order to stay healthy or to put into action. An example of exercise is when you use good judgment. An example of exercise is when you go out and ride your bike.