Determination of the heart rate deflection point by the Dmax method.

OBJECTIVE

Conconi et al. proposed that the point where heart rate departed from linearity in an incremental exercise test was a good indicator of the anaerobic threshold. However, the heart rate deflection points (HRDPs) can not be determined in many subjects. The aim of this study was to determine the heart rate deflection point by the Dmax method and to compare it with the conventional linear method.

SETTING

The study was performed in the Exercise Physiology Laboratory in the Faculty of Medicine, Selçuk University.

PARTICIPANTS

Thirty-two untrained males (aged 18-22) performed a maximal exercise test on a cycle ergometer.

RESULTS

The deflection from linearity of HR could not be detected in nine subjects (28%) by the linear method. The HRDPs could be detected in all subjects by the Dmax method. It was observed that the HR values in the HRDPs determined by both methods were close to the maximal HR values (approximately 90% of maximum). There were high correlations and no differences (p more than 0.05) between the deflection points expressed as oxygen uptake, HR and work rate determined by two methods (correlation coefficients 0.93, 0.93, 0.97, respectively, p less than 0.001).

CONCLUSIONS

The Dmax method is more useful than linear method. The HRDPs of all the people can easily and objectively be found by this method.