title: Physical activity and the progressive change in body composition with aging: current evidence and research issues.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  Both AEX and REX appear to be beneficial in reducing body fat. REX appears to have the additional benefit of increasing fat-free mass.
authors.affiliation: Department of Medicine, University of Vermont, Burlington 05405, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Toth
authors.forename: T
authors.initials: T
authors.lastname: Beckett
authors.forename: E T
authors.initials: ET
authors.lastname: Poehlman
mesh_terms: D000375:Aging / Q000502:physiology*; D001823:Body Composition / Q000502:physiology; D006801:Humans; D012106:Research