Familial resemblance in ventilatory threshold: the HERITAGE Family Study

Purpose: This study investigates the familial resemblance of (V)over dotO(2) at the ventilatory threshold ((V)over dotO(2vt)) from 199 nuclear families (100 White and 99 Black) participating in the HERITAGE Family Study. Methods: (V)over dotO(2vt), (mL.min(-1)) was determined in the sedentary state and again after 20 wk of aerobic cycle ergometer exercise training in 339 individuals (131 parents and 228 of their offspring), aged between 17 and 65 yr. (V)over dotO(2vt) was adjusted for weight, age, fat mass, and fat-free mass by using regression methods. Results: There was evidence for significant familial resemblance in the sedentary state for (V)over dotO(2vt) (maximal heritability = 58% in White and 54% in Black families) and (V)over dotO(2vt)/(V)over dotO(2max) (maximal heritability = 38% in White and 39% in Black families), Spouse, sibling, and parent-offspring relationships for (V)over dotO(2vt) were significant at baseline, suggesting that both genetic and shared environmental factors may contribute to the familial resemblance in the sedentary state. There was a moderate familial component in the response of (V)over dotO(2vt) to aerobic exercise training in Whites (22%) and a larger component in Blacks (51%). In Blacks, the familial effect for (V)over dotO(2vt)/(V)over dotO(2max) appeared to be accounted for by fat and fat-free mass. Conclusion: These results show a strong familial contribution to (V)over dotO(2vt) in the sedentary state and to the response of (V)over dot(O2vt) to aerobic exercise training.