title: Familial resemblance in ventilatory threshold: the HERITAGE Family Study.
abstract: OBJECTIVE
  This study investigates the familial resemblance of VO2 at the ventilatory threshold (VO2vt) from 199 nuclear families (100 White and 99 Black) participating in the HERITAGE Family Study.
  
  
  METHODS
  VO2vt (mL x 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. VO2vt 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 VO2vt (maximal heritability = 58% in White and 54% in Black families) and VO2vt/VO2max (maximal heritability = 38% in White and 39% in Black families). Spouse, sibling, and parent-offspring relationships for VO2vt 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 VO2vt to aerobic exercise training in Whites (22%) and a larger component in Blacks (51%). In Blacks, the familial effect for VO2vt/VO2max appeared to be accounted for by fat and fat-free mass.
  
  
  CONCLUSIONS
  These results show a strong familial contribution to VO2vt in the sedentary state and to the response of VO2vt to aerobic exercise training.
authors.affiliation: Department of Health and Human Performance, Human Performance Laboratory, The University of Montana, Missoula, MT 59812, USA. sgaskill@selway.umt.edu
authors.forename: S E
authors.initials: SE
authors.lastname: Gaskill
authors.forename: T
authors.initials: T
authors.lastname: Rice
authors.forename: C
authors.initials: C
authors.lastname: Bouchard
authors.forename: J
authors.initials: J
authors.lastname: Gagnon
authors.forename: D C
authors.initials: DC
authors.lastname: Rao
authors.forename: J S
authors.initials: JS
authors.lastname: Skinner
authors.forename: J H
authors.initials: JH
authors.lastname: Wilmore
authors.forename: A S
authors.initials: AS
authors.lastname: Leon
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D015308:Anaerobic Threshold / Q000235:genetics*; D000704:Analysis of Variance; D001823:Body Composition; D004777:Environment; D015444:Exercise / Q000502:physiology*; D005190:Family; D005260:Female; D005838:Genotype; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000235:genetics*; D010641:Phenotype; D010809:Physical Fitness / Q000502:physiology; D044469:Racial Groups; D012737:Sex Factors; D014481:United States