Influence of exercise training on physiological and performance changes with weight loss in men

Purpose: The purpose of this study was to examine the physiological effects of a weight-loss dietary regimen with or without exercise. Methods: Thirty -five overweight men were matched and randomly placed into either a control group (C; N = 6) or one of three dietary groups; a diet-only group (D; N = 8), a diet group that performed aerobic exercise three rimes per week (DE; N = 8), and a diet group that performed both aerobic and strength training three times per week (DES; N = 10). Results: After 12 wk, D, DE, and DES d emonstrated a similar and significant (P less than or equal to 0.05) reduct ion in body mass (-9.64, -8.99, and -9.90 kg, respectively) with fat mass c omprising 69, 78, and 97% of the total loss in body mass, respectively. The diet-only group also demonstrated a significant reduction in fat-free mass . Maximum strength, as determined by 1-RM testing in the bench press and sq uat exercise was significantly increased for DES in both the bench press (19.6%) and squat exercise (+32.6%). Absolute peak O-2 consumption was signi ficantly elevated in DE (+24.8%) and DES (+15.4%). There were no difference s in performance during a 30-s Wingate rest for the DE and DES, whereas D d emonstrated a significant decline in peak and mean power output. Resting me tabolic rate (RMR) (kcal.d(-1)) was not significantly different for any of the groups except for the DE group. There were no significant changes in ba sal concentrations of serum glucose, BUN, cortisol, testosterone, and high density lipoprotein (HDL) cholesterol for any of the groups. Serum total ch olesterol and low density lipoprotein (LDL) cholesterol were significantly decreased for all dietary groups. Serum triglycerides were significantly re duced for D and DES at week 6 and remained lower at week 12 for D, while tr iglycerides returned to baseline values for DES. Conclusions: These data in dicate that a weight-loss dietary regimen in conjunction with aerobic and r esistance exercise prevents the normal decline in bat-free mass and muscula r power and augments body composition, maximal strength, and maximum oxygen consumption compared with weight-loss induced by diet alone.