The effects of different exercise regimens on body water compartments in younger and older adults

Abstract

Purpose: The purpose of this study was to analyze existing data and compare the effects of an 8-week intervention of either aerobic exercise, resistance exercise, or a combination of both on changes in total body water (TBW), intracellular (ICW) and extracellular (ECW) water volumes and body composition between groups and compared with a non-exercise control group in younger and older adults. Methods: 69 preor stage-1 hypertensive, overweight or obese, and sedentary adults (age 58 ± 7 y) were randomized to one of three training programs: aerobic (AT), resistance (RT), or a combination of aerobic and resistance (COMB), or a non-exercise control group (CON) for a total of 8 weeks. Body composition and body water compartments were measured with bioelectrical impedance analysis (BIA, InBody720) and a three-day diet diary was recorded at baseline and post-intervention. Statistical analyses were performed on changes between groups, all exercise (INT) vs. control (CON), between sexes, and between younger ( 0.05 for all). INT increased TBW more than CON, but the difference was not significant (0.1 ± 1.3 l and -0.3 ± 1.2 l, P = 0.11, for INT and CON, respectively). COMB had the greatest change in TBW compared with CON (P = 0.05) and had a significantly greater increase in ECW compared with CON (P = 0.03). There was a negative association between age and LBM, TBW, ICW, and ECW volumes (Effect size (ES) > 1.0 for all). TBW, ICW, ECW, and LBM differed between groups in younger adults (P ≤ 0.05 for all), but did not differ between groups in older adults (P > 0.05 for all).