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Heart rate indices of the anaerobic threshold

1983; Lippincott Williams & Wilkins; Volume: 15; Issue: 1 Linguagem: Inglês

10.1249/00005768-198315010-00013

1530-0315

Jeffrey Dwyer, Ronald F. Bybee,

Sports Performance and Training

Although heart rate (HR) cannot be used to identify the anaerobic threshold (AT), it may be used to regulate activity intensity above or below AT. This study examined the HR response and percent maximal HR (%HRmax) at the AT in 20 young women. The AT, VO2max, and HRmax were assessed during incremental (25 W each min) cycle exercise to exhaustion. Ventilation and gas exchange were measured ever 30 s, and HR was measured each minute. Anaerobic threshold was identified by departure from linearity of the oxygen-ventilation equivalent (VEo2), pulmonary ventilation (VE), and Vco2 relative to VO2. Heart rate at AT was found by regressing HR on VO2 with individual equations. The mean (±SD) VO2max was 38.4 ± 4.7 ml·min-1·kg-1 with HRmax of 183.0 ± 8.0 bpm. Anaerobic threshold averaged 27.0 ml·min-1·kg11 (70.1% VO2max) with corresponding HR of 158.4 ± 12.4 bpm (86.3% HRmax). A zone of non-uniform work stress with respect to AT was found between 75–90% HRmax (58–75% VO2max): exercise at any intensity in this zone results in as few as one or as many as 14 subjects working above their AT. If AT represents a transition point in metabolic stress, it may be a better basis for activity prescription than an arbitrary percent VO2max or percent HRmax. Heart rate can be used to regulate activity above or below AT, but this requires individual assessment of HRAT because the correlation (r) between %HRmaxAT and %Vo2maxAT was 0.60. Exercise between 50–85% VO2max, or 70–90% HRmax results in dissimilar work stress in subjects with different AT but similar VO2max. More uniform activity prescriptions, with respect to intensity, could be attained if work is equated on the basis of AT.