A 3-year longitudinal study on body composition changes in the elderly: Role of physical exercise

Background: Cross-sectional data have shown that sarcopenia and fat accumulation are associated with aging and can be limited by structured physical training. However, it is often difficult to maintain a long-term compliance to training programs. It is not clear whether leisure-time physical activity is effective in preventing sarcopenia and fat accumulation. Objectives: (i) To investigate Longitudinal body composition changes in a population of elderly people in good apparent health. (ii) To evaluate the impact of leisure-time physical activity on muscle mass and characteristic as reflected by total body potassium per fat-free soft tissue (TBK/FFST), and on fat accumulation. Design: Longitudinal evaluation over 3 years, of body composition changes in 74 healthy men and 66 women, over 65 years old. Body fat and FFST were analyzed by dual-energy X-ray absorptiometry and TBK by whole-body K-40 counter. Physical activity was analyzed by a specific questionnaire. Results: Despite a stable total body weight, FFST and appendicular skeletal muscle mass slightly decreased (-0.3 +/- 1.4 and -0.2 +/- 2.2 kg, P<0.01, respectively) as well as the TBK/FFST (-4.1 +/- 6.3 mmot/kg, P<0.001), over the 3-year period. Body fat increased significantly (0.6+/- 2.2 kg, P<0.0001), and it accumulated mainly in the abdomen (0.4+/- 1.5 kg, P<0.01). Multiple regression analysis showed that body composition changes were related mainly to body weight changes. Nevertheless, positive linear correlations were observed between the degree of engagement in leisure-time physical activity and FFST (P<0.01), appendicular skeletal muscle mass (P<0.05), TBK/FFST (P<0.05), whereas negative correlation was observed with total and truncal fat (P< 0.01). Conclusions: Mild but significant decline in muscle mass and its TBK content, and body fat accumulation were observed over a 3-year period in healthy elderly subject: leisure-time physical activity does not seem to prevent them. However, a higher level of physical activity is associated with higher muscle mass and TBK content, and less total and truncal fat. (C) 2005 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.