The aim of the present study was to investigate the effect of long-term continuation of low-intensity exercise training on weight maintenance, substrate metabolism, and beta-adrenergic-mediated fat oxidation in weight-reduced obese men. Preceding this part of the study, subjects lost 15 +/- 6 kg of body weight by energy restriction with or without low-intensity exercise training. Twenty-nine subjects (diet group, n = 15; diet + exercise group, n = 14) participated in the follow-up study of 40 weeks in which the former diet + exercise group continued their exercise training program. Pre- and postfollow-up, measurements of body weight, body composition, maximal aerobic capacity and substrate oxidation during rest, exercise, and recovery with or without infusion of the beta-adrenergic antagonist, propranolol (PRP), were performed. Over the follow-up period, body weight, fat mass, and fat free mass increased in both groups (P <.0001) without differences between groups. Attendance at exercise training sessions was negatively correlated with regain of body weight (r = -.6, P <.05). Relative fat oxidation, energy expenditure, and beta-adrenergic-mediated fat oxidation during rest, exercise, and recovery were maintained over the follow-up period in both groups. Continuation of low-intensity exercise training after weight reduction did not limit regain of body weight, unless exercise training was frequently performed. Relative (beta-adrenergic-mediated) fat oxidation and energy expenditure were maintained at postdiet level whether or not low-intensity exercise training was performed during follow-up.
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