53. Swallow, J. G., T. Garland, Jr., P. A. Carter, W.-Z. Zhan, and G. C. Sieck. 1998. Effects of voluntary activity and genetic selection on aerobic capacity in house mice (Mus domesticus).
Journal of Applied Physiology 84:69-76.

Abstract

An animal model was developed to study effects on components of exercise physiology of both "nature" (10 generations of genetic selection for high voluntary activity on running wheels) and "nurture" (7-8 wk of access or no access to running wheels, beginning at weaning). At the end of the experiment, mice from both wheel-access groups were significantly lighter in body mass than mice from sedentary groups. Within the wheel-access group, a statistically significant, negative relationship existed between activity and final body mass. In measurements of maximum oxygen consumption during forced treadmill exercise (VO₂max), mice with wheel access were significantly more cooperative than sedentary mice; however, trial quality was not a significant predictor of individual variation in VO₂max. Nested two-way analysis of covariance demonstrated that both genetic selection history and access to wheels had significant positive effects on VO₂max. A 12% difference in VO₂max existed between wheel-access selected mice, which had the highest mass-corrected VO₂max, and sedentary control mice, which had the lowest. The respiratory exchange ratio at VO₂max was also significantly lower in the wheel-access group. Our results suggest the existence of a possible genetic correlation between voluntary activity levels (behavior) and aerobic capacity (physiology).