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 familie s (100 White and 99 Black) participating in the HERITAGE Family Study. Meth ods: (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 i ndividuals (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 signific ant familial resemblance in the sedentary state for (V)over dotO(2vt) (maxi mal 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 Bl ack families), Spouse, sibling, and parent-offspring relationships for (V)o ver dotO(2vt) were significant at baseline, suggesting that both genetic an d shared environmental factors may contribute to the familial resemblance i n the sedentary state. There was a moderate familial component in the respo nse 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)ov er 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 t o (V)over dotO(2vt) in the sedentary state and to the response of (V)over d ot(O2vt) to aerobic exercise training.