Familial aggregation ofV˙o 2 max response to exercise training: results from the HERITAGE Family Study

Abstract

The aim of this study was to test the hypothesis that individual differences in the response of maximal O₂ uptake (V˙o_{2 max}) to a standardized training program are characterized by familial aggregation. A total of 481 sedentary adult Caucasians from 98 two-generation families was exercise trained for 20 wk and was tested for V˙o_{2 max} on a cycle ergometer twice before and twice after the training program. The mean increase inV˙o_{2 max} reached ∼400 ml/min, but there was considerable heterogeneity in responsiveness, with some individuals experiencing little or no gain, whereas others gained >1.0 l/min. An ANOVA revealed that there was 2.5 times more variance between families than within families in theV˙o_{2 max} response variance. With the use of a model-fitting procedure, the most parsimonious models yielded a maximal heritability estimate of 47% for the V˙o_{2 max} response, which was adjusted for age and sex with a maternal transmission of 28% in one of the models. We conclude that the trainability ofV˙o_{2 max} is highly familial and includes a significant genetic component.