A Prospective Study of Physical Activity Intensity and Change in Adiposity in Middle-Aged Women

Purpose. To determine the extent to which objectively measured intensity of physical activity (PA) predicts change in body fat (BF%) in women. Design. Prospective cohort study of PA intensity and body composition in middle-aged women. Setting. The study took place in a metropolitan Mountain West community. Subjects. Two hundred and twenty-eight women participated in two assessment periods separated by 20 months. Measures. Each assessment period consisted of seven consecutive days of monitoring, followed by body composition testing. Analysis. The general linear model using partial correlations and Mantel-Haenszel χ2 tests were performed. Results. At baseline and follow-up, women who participated in vigorous PA were leaner than women who participated in moderate or light PA (p < .05). Longitudinal results indicated that a greater proportion of women who decreased PA intensity over the 20 months also increased BF% (66%), compared to participants who increased or maintained PA intensity (47%) (p < .05). Conclusions. PA intensity seems to play a role in long-term weight maintenance. Reducing PA intensity increases the risk of BF% gain in women. Efforts to help women maintain PA intensity along with other weight management strategies may prove beneficial in preventing unwanted body fat gain in middle-aged women.