FAMILIAL RESEMBLANCE FOR VO2MAX IN THE SEDENTARY STATE - THE HERITAGEFAMILY STUDY

This study investigates the familial resemblance of maximal oxygen upt ake (Vover dotO(2max)) based on data from 86 nuclear families of Cauca sian descent participating in the HERITAGE Family Study. In the curren t study, Vover dotO(2max) was measured twice on a cycle ergometer in 4 29 sedentary individuals (170 parents and 259 of their offspring), age d between 16 and 65 yr. The Vover dotO(2max) was adjusted by regressio n 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 dete rmined by underwater weighing. Evidence for significant familial resem blance 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 t he familial resemblance for Vover dot O-2max. Maximal heritability est imates were at least 50%, a value inflated to an undetermined degree b y 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 i n part with mitochondrial inheritance, reaching about 30%. These resul ts suggest that genetic and nongenetic factors as well as maternal inf luences contribute to the familial aggregation of Vover dotO(2max) in sedentary individuals.