Familial resemblance for VO2max in the sedentary state:: the HERITAGE Family Study

This study investigates the familial resemblance of maximal oxygen uptake (Vover dotO(2max)) based on data from 86 nuclear families of Caucasian descent participating in the HERITAGE Family Study. In the current study, Vover dotO(2max) was measured twice on a cycle ergometer in 429 sedentary individuals (170 parents and 259 of their offspring), aged between 16 and 65 yr. The Vover dotO(2max) was adjusted by regression procedures for the effects of 1) age and sex; 2) age, sex, and body mass; and 3) age, sex, body mass, fat mass, and fat-free mass, as determined by underwater weighing. Evidence for significant familial resemblance was observed for each of the three Vover dotO(2max) phenotypes. Spouse, sibling, and parent-offspring correlations were significant, suggesting that both genetic and environmental factors contribute to the familial resemblance for Vover dot O-2max. Maximal heritability estimates were at least 50%, a value inflated to an undetermined degree by nongenetic factors. The hypothesis of maternal inheritance, with the father's contribution being environmental, was also found to fit the data with estimates of maternal heritability, potentially associated in part with mitochondrial inheritance, reaching about 30%. These results suggest that genetic and nongenetic factors as well as maternal influences contribute to the familial aggregation of Vover dotO(2max) in sedentary individuals.