Physical activity and the progressive change in body composition with aging: current evidence and research issues.

Abstract

The purpose was to review studies that have examined the effect of aerobic (AEX) or resistance exercise (REX) on body composition in older individuals (>55 yr). Our goal was to examine the effect of these two exercise paradigms on fat mass and fat-free mass and to consider those factors that may explain variability in findings among studies. We conducted a literature search (Medline, 1984-1999) for intervention studies (at least 2 months in duration) that have examined the independent effect of either REX or AEX on body composition in older individuals. AEX decreased fat mass (range: -0.4 to -3.2 kg) but had little effect on fat-free mass. The change in fat mass with AEX was related to the duration of the exercise program (r = 0.51; P < 0.02) but not to body composition methodology. In contrast, REX reduced fat mass (range: -0.9 to -2.7 kg) and increased fat-free mass (range: 1.1 to 2.1 kg). Changes in body composition with REX were not related to body composition methodology or the duration of the exercise program. Both AEX and REX appear to be beneficial in reducing body fat. REX appears to have the additional benefit of increasing fat-free mass.