Abstract
Aims of this study were: to verify if Recurrence Quantification Analysis (RQA) of Heart Rate Variability (HRV) time series could determine both ventilatory thresholds in individuals with different fitness levels, and to assess the validity of RQA method compared to gas-exchange method (GE). The two thresholds were estimated in thirty young individuals during incremental exercise on cycle-ergometer: Heart rate (HR), Oxygen consumption (VO2) and Workload were measured by the two methods (RQA and GE). Repeated measures ANOVA was used to assess main effects of methods and methods-by-groups interaction effects for HR, VO2 and Workload at aerobic (AerT) and anaerobic (AnT) thresholds. Validity of RQA at both thresholds was assessed for HR, VO2 and Workload by Ordinary Least Products (OLP) regression, Typical Percentage Error (TE), Intraclass Correlation Coefficients (ICC) and the Bland Altman plots. No methods-by-groups interaction effects were detected for HR, VO2 and Workload at AerT and AnT. The OLP analysis showed that at both thresholds RQA and GE methods had very strong correlations (r >0.8) in all variables (HR, VO2 and Workload). Slope and intercept values always included the 1 and the 0, respectively. At AerT the TE ranged from 4.02% (5.48 bpm) to 10.47% (8.53 Watts) (HR and Workload, respectively) and in all variables ICC values were excellent (≥0.85). At AnT the TE ranged from 2.53% (3.98 bpm) to 6.64% (7.81 Watts) (HR and Workload, respectively) and in all variables ICC values were excellent (≥0.90). Therefore, RQA of HRV time series is a new valid approach to determine both ventilatory thresholds in individuals with different physical fitness levels, it can be used when gas analysis is not possible or not convenient.
Citation: Zimatore G, Falcioni L, Gallotta MC, Bonavolontà V, Campanella M, De Spirito M, et al. (2021) Recurrence quantification analysis of heart rate variability to detect both ventilatory thresholds. PLoS ONE 16(10):
e0249504.
https://doi.org/10.1371/journal.pone.0249504
Editor: Laurent Mourot, University of Bourgogne France Comté, FRANCE
Received: March 14, 2021; Accepted: September 23, 2021; Published: October 7, 2021
Copyright: © 2021 Zimatore et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All relevant data are within the manuscript and its Supporting Information files.
Funding: The author(s) received no specific funding for this work.
Competing interests: The authors have declared that no competing interests exist.
Abbreviations:
HR,
Heart Rate; HRV,
Heart Rate Variability; CPET,
Cardiopulmonary exercise test; RPE,
Rate of Perceived Exertion; RQA,
Recurrence Quantification Analysis; GE,
Gas Exchange; AerTGE,
Aerobic Gas Exchange Threshold; AnTGE,
Anaerobic Gas Exchange Threshold; AerTRQA,
Aerobic Recurrence Quantification Analysis Threshold; AnTRQA,
Anaerobic Recurrence Quantification Analysis Threshold; DET,
percent of determinism, the percent of recurrence points which form diagonal lines; LAM,
percent of laminarity, the percent of recurrence points which form vertical lines; BMI,
Body Mass Index; BIA,
Bioelectrical Impedance Analysis; FM%,
Fat Mass percentage; VO2,
Volume of Oxygen consumption; VCO2,
Volume of Carbon dioxide production; VE,
ventilation; OLP,
Ordinary Least Product; TE,
Typical percentage Error; ICC,
Intraclass correlation coefficients; IC,
confidence interval; RER,
Respiratory Exchange Ratio; LoA,
Limit of agreement