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 chi2 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.