Effects of voluntary exercise on spontaneous physical activity and food consumption in mice: Results from an artificial selection experiment

Abstract

We evaluated the effect of voluntary exercise on spontaneous physical activity (SPA) and food consumption in mice from 4 replicate lines bred for 57 generations for high voluntary wheel running (HR) and from 4 non-selected control (C) lines. Beginning at ~24 days of age, mice were housed in standard cages or in cages with attached wheels. Wheel activity and SPA were monitored in 1-min intervals. Data from the 8th week of the experiment were analyzed because mice were sexually mature and had plateaued in body mass, weekly wheel running distance, SPA, and food consumption. Body mass, length, and masses of the retroperitoneal fat pad, liver, and heart were recorded after the 13th week. SPA of both HR and C mice decreased with wheel access, due to reductions in both duration and average intensity of SPA. However, total activity duration (SPA+wheel running; min/day) was ~1/3 greater when mice were housed with wheels, and food consumption was significantly increased. Overall, food consumption in both HR and C mice was more strongly affected by wheel running than by SPA. Duration of wheel running had a stronger effect than average speed, but the opposite was true for SPA. With body mass as a covariate, chronic wheel access significantly reduced fat pad mass and increased heart mass in both HR and C mice. Given that both HR and C mice housed with wheels had increased food consumption, the energetic cost of wheel running was not fully compensated by concomitant reductions in SPA. The experiment demonstrates that both duration and intensity of both wheel running and SPA were significant predictors of food consumption. This sort of detailed analysis of the effects of different aspects of physical activity on food consumption has not previously been reported for a non-human animal, and it sets the stage for longitudinal examination of energy balance and its components in rodent models.

Comparison of Diet versus Exercise on Metabolic Function and Gut Microbiota in Obese Rats

“…This was accomplished with a moderate reduction of 20-25% of ad libitum HFD. In light of mixed results in both animals and humans suggesting that exercise may (7) or may not (13) lead to a compensatory increase in energy intake, we measured energy intake of the Ex group fed ad libitum HFD. We found no Ex-mediated increase in energy intake, arguing against the hypothesis that exercise alone is ineffective in reducing body weight due to a compensatory increase in dietary energy, at least in this obesity-prone male rat model.…”

Maternal exposure to Western diet affects adult body composition and voluntary wheel running in a genotype-specific manner in mice

“…Although HR lines experienced the same directional selection, each replicate line (and sexes within lines) differed in response time to the selection pressure and mean voluntary wheel running [45], as well as other phenotypes [30, e.g., 37, 46]. Thus, the replicate HR lines have had “multiple solutions” [47] and may be expected to differ in response to manipulation of maternal diet. When the interaction between diet and line was statistically significant, we checked the P value for differences of least-squares means for effect of diet on each line (SAS Procedure Mixed).…”

Hormones and the Evolution of Complex Traits: Insights from Artificial Selection on Behavior

“…Although the HR lines have evolved to be smaller in both body mass and length under most conditions (Swallow et al 1999;Kelly et al 2006;Copes et al 2015), it is not entirely clear if this would be beneficial for sustained, endurance-type exercise. A similar question concerns their generally reduced body fat (Swallow et al 2001;Girard et al 2007;Nehrenberg et al 2009; but see Vaanholt et al (2007b); Meek et al (2014); Acosta et al (2015)).…”