A comparison of the point of deflection from linearity of heart rate and the ventilatory threshold in the determination of the anaerobic threshold in Indian boys.

The purpose of the study was to assess whether the point of deflection from linearity of heart rate (HRD) could be used as an alternative method to determine the ventilatory threshold (VT) in Indian (Bengali) boys that represents the determination of the anaerobic threshold (AT), and also to standardize an exercise test to be effective in eliciting AT in Indian (Bengali) boys by using HRD. Twenty six (26) boys with a mean age of 12.8 (+/-1.18) years performed a graded maximal exercise test on a treadmill to determine peak VO(2), HRD and VT. The mean peak VO(2), weight related peak VO(2), peak pulmonary ventilation, and peak heart rate of the boys were found to be 1.75 l/min, 47.1 ml/kg/min, 66.9 l/min and 200.2 beats/min respectively. There were no significant differences between mean VO(2), weight related VO(2), pulmonary ventilation (VE), heart rate and respiratory exchange ratio (RER) that were measured at VT and HRD. The mean VO(2) measured at VT and HRD was found to be 1.46 and 1.45 l/min, which were about 84% and 83% of their respective peak values. Linear regression analysis revealed a correlation of 0.94 (p<0.01) between VO(2) measured at VT and VO(2) measured at HRD, so the present study indicates that the point of deflection from linearity of heart rate (HRD) may be an accurate predictor of VT in most but not all boys.