By: Anya Sailey
There are many claims of “boosted metabolism” as a result of exercise in the fitness industry today. Both journal articles discussed herein address the human metabolism and energy expenditure in relation to post-exercise thermogenesis. Additionally, both articles seek to disprove the common theory that “the human metabolic rate remains elevated for up to 48 hours post-exercise” (Bingham et. al., 1989). The American Journal of Clinical Nutrition article discusses the efficacy of several weight-loss strategies pertaining to variation in macronutrient distribution. This article’s main research topic seeks to “investigate whether or not there is a sustained effect of either moderate or intense exercise on metabolic rate.” (Freedman-Akabas et al., 1985) The British Journal of Nutrition article authors seek to determine “whether or not there is a sustained enhancement in metabolic rate following physical exercise.” (Bingham et. al., 1989) The significance of this experiment relates to the author’s challenge of the efficacy of weight-control solely based upon the exercise component of a fitness program.
The objective of both articles is to investigate the effect of moderate or intense exercise on metabolism. The first study used VO2 (volume of Oxygen consumption) to evaluate the fitness level of participants before and af
ter exercise. Researchers found that VO2 levels returned to their baseline values 40 minutes after exercising and remained for at least 3 hours, regardless of gender or fitness level. In the second study, volunteers’ vital signs, physiological compositions, intakes/outputs, standardized diets, and exercise methods were observed over time. Researchers found that metabolic rates did not change over time when measured up to 24 hours post-exercise.
Both articles concluded that there are no significant sustained effects on resting metabolic rates post-exercise. (Freedman-Akabas et al., 1985, Bingham et al., 1989) Both studies show that the human metabolism is not significantly “boosted” as a result of exercise for a longer period of time than the duration of the exercise itself. This finding is discouraging for marketing schemes targeting those who want to believe that their metabolism will increase as a result of a certain product or repeated physical exercise. Both studies highlight the beneficial effects of exercise, and conclude that the component of sustainability in terms of physical exercise is crucial: it is not possible to expect significant results in the resting period between exercises. Additionally, both articles stress the importance of diet in terms of weight-control program implementation.
Bibliography
Bingham, S.A., Goldberg, G.R., Coward, W.A., A.M. Prentice, and J.H. Cummings. (1989). The effect of exercise and improved physical fitness on basal metabolic rate. In British Journal of Nutrition 61, 155-173.
Freedman-Akabas, S., Colt, E., H. Kisseleff, and F. Xavier Pi-Sunyer. (1985). Lack of sustained increase in VO2 following exercise in fit and unfit subjects. In American Journal of Clinical Nutrition 41, 545-549.