Estimation of maximal heart rate using the relationship between heart rate variability and exercise intensity in 40-67 years old men.

摘要

Large interindividual variation in maximal heart rate (HR(max)) may not be accounted for by age alone. In order to evaluate a novel method in the prediction of HR(max), this study examined the profile of HR variability (HRV) during exercise in 40-67 years old men (n = 74). R-R intervals were recorded during supine rest and during a graded exercise test by cycle ergometry until exhaustion. A third-degree polynomial function was fitted to the HRV data recorded during exercise to represent the HRV profile of each subject. The instantaneous beat-to-beat R-R interval variability (SD1), high (HF) and low frequency power decreased between all consecutive exercise intensities (P < 0.033). The relationship between HR(max) and a variable illustrating the declining rate of HF (HR(HF50%)) was stronger (r = 0.50, P < 0.001) than between HR(max) and age (r = -0.36, P < 0.01). The regression analysis showed that a more accurate estimation of HR(max) was attained when HRV was used in the equation in addition to age: HR(max) = 160.633-0.603(age) + 0.441(HR(HF50%)) (SEE = 9.8 bpm vs. 11.6 bpm in the equation based on age alone). The decline of HRV during incremental exercise seems to be useful for accurate estimation of maximal heart rate.