Familial aggregation of submaximal aerobic performance in the HERITAGE Family study

Abstract

This study examines the contribution of genetic factors to submaximal aerobic performance phenotypes measured before and after 20 wk of endurance training. Submaximal oxygen consumption (V̇O2) at three power outputs, 50 W (V̇O250W), 60% (V̇O260%) and 80% (V̇O280%) of V̇O2max and power outputs at 60% (PO60%) and 80% (PO80%) of V̇O2max were measured during cycle ergometer exercise tests in 483 subjects from 99 white families participating in the HERITAGE Family study. The baseline phenotypes were adjusted for the effects of age, sex, and body mass using stepwise multiple regression procedures. The response phenotypes, computed as the difference (Δ) between the posttraining and baseline measures, were adjusted for age, sex, and the baseline value. All submaximal exercise phenotypes measured at baseline and in response to training were characterized by a significant familial resemblance. Maximal heritabilities of the baseline phenotypes range from 48% to 74% with significant spouse, sibling, and parent-offspring correlations. The hypothesis of maternal inheritance where mother-offspring and sibling correlations were forced to be equal was found to fit the data for V̇O260%, V̇O280% and PO80%. For the response phenotypes, the maximal heritabilities tended to be lower (23–57%) with a significant maternal inheritance for ΔV̇O260%, ΔPO60%, and ΔPO80%. These results suggest that the submaximal working capacities of sedentary subjects and their responses to endurance training are influenced by familial/genetic factors with a significant contribution of maternal inheritance.