A modified D-max method to estimate heart rate at a ventilatory threshold during an incremental exercise test

Authors:
Publisher website
Google Scholar
Abstract
The purpose of this study was to design a modified D-max method to determine heart rate at a ventilatory threshold (HRVT) and to investigate whether this method would be valid during incremental exercise tests. The HRVT was estimated from a new parameter defined as HR at the maximal difference point between linearly- and quadratically approximated HR trends (modified D-max method). HR and ventilatory gas data for 105 subjects (53 males and 52 females; 38.26 ± 12.06 years; 166.62 ± 8.21 cm; 65.31 ± 11.10 kg) were simultaneously collected during an incremental treadmill test to evaluate the validity of the modified D-max method. Reference HRVTs were manually identified from the ventilatory gas data by an experienced sports physiologist and compared with those estimated by the HR parameter. A strong positive correlation (r = 0.71, p <; 0.01) and a low HR difference of 9.94 ± 7.10 bpm between the reference and estimated HRVTs were obtained. The results indicate that the modified D-max method outperforms the conventional D-max method (r = 0.53, p <; 0.01), the three-piece linear regression lines method (r = 0.42, p <; 0.01), and the parallel straight line slope method (r = 0.57, p <; 0.01). Furthermore, the modified D-max method improves the predictive accuracy of HRVTs by combining its result with subject's age. The combined parameters have a strong positive correlation with the reference HRVTs (r = 0.74, p <; 0.01) and a lower HR difference of 9.40 ± 6.91 bpm. The results suggest that the modified D-max method is highly applicable to predicting HRVTs during incremental exercise tests and also improves HRVT detection accuracy by combining its result with the subject's age.

This publication has 12 references indexed in Scilit: