title: Determination of Anaerobic Threshold by Heart Rate or Heart Rate Variability using Discontinuous Cycle Ergometry.
abstract: The purpose was to determine if heart rate (HR) and heart rate variability (HRV) responses would reflect anaerobic threshold (AT) using a discontinuous, incremental, cycle test. AT was determined by ventilatory threshold (VT). Cyclists (30.6±5.9y; 7 males, 8 females) completed a discontinuous cycle test consisting of 7 stages (6 min each with 3 min of rest between). Three stages were performed at power outputs (W) below those corresponding to a previously established AT, one at W corresponding to AT, and 3 at W above those corresponding to AT. The W at the intersection of the trend lines was considered each metric's "threshold". The averaged stage data for Ve, HR, and time- and frequency-domain HRV metrics were plotted versus W. The W at the "threshold" for the metrics of interest were compared using correlation analysis and paired-samplet-test. In all, several heart rate-related parameters accurately reflected AT with significant correlations (p≤0.05) were observed between AT W and HR, mean RR interval (MRR), low and high frequency spectral energy (LF and HR, respectively), high frequency peak (fHF), and HFxfHF metrics' threshold W (i.e., MRRTW, etc.). Differences in HR or HRV metric threshold W and AT for all subjects were less than 14 W. The steady state data from discontinuous protocols may allow for a true indication of steady-state physiologic stress responses and corresponding W at AT, compared to continuous protocols using 1-2 min exercise stages.
authors.affiliation: Department of Health and Kinesiology, The University of Texas at San Antonio, San Antonio, TX, USA.
authors.forename: Sung Wook
authors.initials: SW
authors.lastname: Park
authors.affiliation: Department of Health and Kinesiology, The University of Texas at San Antonio, San Antonio, TX, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Brenneman
authors.affiliation: Department of Health and Kinesiology, The University of Texas at San Antonio, San Antonio, TX, USA.
authors.forename: William H
authors.initials: WH
authors.lastname: Cooke
authors.affiliation: Department of Health and Kinesiology, The University of Texas at San Antonio, San Antonio, TX, USA.
authors.forename: Alberto
authors.initials: A
authors.lastname: Cordova
authors.affiliation: Department of Health and Kinesiology, The University of Texas at San Antonio, San Antonio, TX, USA.
authors.forename: Donovan
authors.initials: D
authors.lastname: Fogt
keywords: Heart rate; anaerobic threshold; cycling; heart rate variability