Is there spontaneous energy expenditure compensation in response to intensive exercise in obese youth?

Abstract

Background: Physical activity is mainly used in weight control strategies to favour energy expenditure. Some evidence suggests that exercise might not have the expected impact on energy balance, and may actually cause a decrease in the subsequent physical activity energy expenditure.

Objective: To question the impact of an acute exercise session of varying intensities on daily energy expenditure in lean and obese adolescents.

Methods: Data from three separate studies conducted in lean and obese 12-15 years old adolescents (study 1: 12 obese; study 2: 10 obese and nine lean; study 3: 15 obese) have been used. Daily energy expenditure (DEE) was assessed in studies 1 and 2 during an exercise condition with an exercise bout at 70%VO(2max) (EX) and a rest day (REST) (using Actiheart and Armbands, respectively). In study 3, DEE was assessed in calorimetric chambers during (i) a high intensity exercise condition (HIE - 75%VO(2max)) and (ji) a condition with a low intensity exercise (LIE - 40%VO(2max)) and (iii) a rest condition (REST).

Results: Morning energy expenditure was significantly higher during the exercise conditions whatever the intensity compared with rest. Afternoon energy expenditure was significantly lower following HIE compared to the rest condition in studies 2 and 3. Afternoon energy expenditure was not significantly different between LIE and REST in study 2. Total DEE was not significantly different between conditions in the three studies.

Conclusion: Obese adolescents seem to show a compensatory response to an acute session of HIE (>70%VO(2max)) by decreasing their following physical activity energy expenditure. Although HIE favours body composition, physical fitness and metabolic profile improvements, this induced compensatory energy expenditure response has to be considered to optimize its effect on weight loss.

Keywords: Childhood obesity; energy expenditure; physical activity.