Agreement between the Heart Rate Variability Threshold and Ventilatory Threshold in Young Women: Impact of Cardiac Parasympathetic Status and Cardiorespiratory Fitness

The heart rate variability threshold (HRVT) is a useful and inexpensive alternative to estimate the ventilatory threshold (VT). However, its validity in women remains underexplored. We investigated the agreement between HRVT and VT in young women and the influence of cardiac parasympathetic status and cardiorespiratory fitness (CRF). Sixty-one women [Age: 24.5 +/- 4.6 years, BMI: 23.4 +/- 2.6 kg/m(2), VO(2)max: 36.6 +/- 6.1 (mL (kg.min)(-1))] underwent a maximal exercise test on a treadmill. We assessed HRVT using four methods: HRVTvisual, HRVTDmax, HRVT3ms, HRVT1ms. Low bias and limits of agreement were observed between VT and HRVTvisual [-.1 (-1.5. 1.3) km/h] and HRVTDmax [-.1 (-1.6, 1.4) km/h] methods. Higher limits of agreement were observed for HRVT3ms [.1 (-2.1, 2.1) km/h] and HRVT1ms [.4 (-1.8, 2.7) km/h]. In conclusion, acceptable agreement was observed between VT and HRVT in women, mainly when visual and Dmax methods were used for HRVT assessment.