The epidemiology of physical activity and physical function in older people.

A primary goal of studies of successful aging is to identify the modifiable factors related to the plasticity of higher physical function; however, little is known about the relationship between habitual physical activity (especially that of lower- to moderate-intensity) and the maintenance of day-to-day functioning in older people. The purpose of this paper is to address the question of how patterns of physical activity translate into altered physical function among healthy older populations. In this paper, physical activity is classified as a behavior, whereas physical function is classified as performance, comprised of a series of increasingly integrated steps. Recent data from several epidemiologic studies suggest that physical activity is associated with the maintenance of more basic components of physical function, as well as with higher-order task or goal-oriented functions in healthy older people. Moreover, higher levels of physical activity appear to be associated with better functioning, even in those with already-existing chronic disease. Recent CDC/ACSM health recommendations call for incorporating at least 30 min of any activity into the daily schedule. Therefore, regular participation in activities of moderate intensity (such as walking, gardening, house/yard work) should be encouraged among the general older community.