Journal of Applied Physiology, Vol 62, Issue 2 539-544, Copyright © 1987 by American Physiological Society
Heredity and overfeeding-induced changes in submaximal exercise VO2
A. Tremblay, E. T. Poehlman, A. Nadeau, J. Dussault and C. Bouchard
The present study investigated the role of heredity in determining changes
in the energy cost of submaximal exercise in response to short-term
overfeeding. Six pairs of monozygotic twins were subjected to a 1,000
kcal/day surplus for 22 days with careful experimental controls over food
intake and physical activities. O2 consumption (VO2) was measured during a
submaximal treadmill exercise test 165 min postprandially before and the
morning after the overfeeding protocol. As expected, overfeeding induced
significant increases in body weight and fat mass. No significant increase
in mean exercise VO2 was observed after overfeeding. However, the
interindividual variation in overfeeding-induced changes in exercise VO2
was large and not randomly distributed. When comparing intrapair variance
for changes in exercise VO2 to interpair variance, a moderate to high
within-pair resemblance in response, i.e., a genotype-overfeeding
interaction, was observed. Changes in exercise VO2 were positively
correlated with those in postexercise levels of blood catecholamines,
particularly epinephrine. A negative correlation was found between changes
in exercise VO2 and body fat gain. These results are consistent with the
concept of a role for the sympathoadrenal system in the regulation of
adaptive thermogenesis and the predisposition to store fat. Moreover, these
data suggest that the sensitivity to adapt in exercise energy expenditure
after overfeeding is inherited to a significant extent.
