CLASSIFICATION OF RESPONDERS AND NON-RESPONDERS TO STANDARDIZED TRAINING: THE HERITAGE FAMILY STUDY

546 It is unclear how to classify responders or non-responders to exercise training. In subjects with similar body mass and fitness levels, one can use 1) absolute [ABS] change in VO2max (ml/min) or (ml/kg/min) or 2) relative [REL] change (%) in both. Because HERITAGE subjects were heterogeneous (age=16-65 yr, body mass=40-138 kg, VO2max=1172-4434 ml/min and 15-57 ml/kg/min), we looked at 431 subjects in the lowest, middle two and highest quartiles of ABS and REL change in VO2max. For REL change, those with the lowest VO2max had the largest % change in ml/min and in ml/kg/min. For ABS change, those with the highest VO2max (ml/min) weighed most and changed most. There was no difference in initial VO2max (ml/kg/min) among those who had different ABS changes in ml/kg/min. More males were in the high response group for ABS changes (greater body mass) but fewer males were in that group for REL changes, i.e., women had lower values. There were no group differences in number of Blacks or Whites or in body composition. Group differences in response to submaximal exercise were related to body mass or fitness. It is concluded that body mass and fitness influence the classification of response to training by heterogeneous groups. Changes in VO2max (ml/min) should be statistically adjusted for age, sex, body mass and body composition. Supported by NIH-NHLBI grants