Energy Conservation and Exercise Dependence: A Sympathetic Arousal Hypothesis

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exercise, dieting, metabolic rate, exercise dependence, hormones, sympathetic arousal, endorphins, norepinephrine, epinephrine, oxygen consumption, fitness levels, exercise training


The present article reviews a wide range of studies which suggest that energy balance mechanisms are affected by food restriction and exercise training. Specifically, food restriction produces adaptive decreases in basal metabolic rate, a decrease in the energy utilized in the performance of a specific task, and an increase in the efficiency of food utilization following resumption of pre-restriction feeding patterns. Exercise training produces an adaptive decrease in the energy required to perform aspecific task and in the hormonal output to a standard work task. Conflicting evidence exists on the combined effects of exercise and dietingon energy conservation. This energy balance information is used as the basis for the development of a sympathetic arousal hypothesisof exercise dependence. We propose that exercise dependence is mediated by adaptive reductions in sympathetic output to exercisetasks as a result of training, requiring the individual to engage in heightened levels of activity to produce pre-training levels of physiological arousal.

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Citation / Publisher Attribution

Medicine and Science in Sports and Exercise, v. 19, issue 2, p. 91-99