Recovery of Heart Rate Variability After Exercise Under Hot Conditions: The Effect of Relative Humidity

[EN] Introduction The aim of this study was to analyze changes in heart rate variability (HRV) during exercise in hot environments and recovery to baseline values depending on relative humidity. Methods Ten recreational runners participated in this study. Each participant performed 2 trials consisti...

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Bibliographic Details
Authors: Abellán Aynés, Oriol, López Plaza, Daniel, Alaid, Fernando, Naranjo Orellana, José, Manonelles, Pedro
Format: article
Status:Published version
Publication Date:2019
Country:España
Institution:Universidad de León
Repository:BULERIA. Repositorio Institucional de la Universidad de León
OAI Identifier:oai:buleria.unileon.es:10612/25004
Online Access:https://hdl.handle.net/10612/25004
Access Level:Open access
Keyword:Deporte
sympathetic
autonomic nervous system
hyperthermia
parasympathetic
Description
Summary:[EN] Introduction The aim of this study was to analyze changes in heart rate variability (HRV) during exercise in hot environments and recovery to baseline values depending on relative humidity. Methods Ten recreational runners participated in this study. Each participant performed 2 trials consisting of 30 min of continuous running under hot and dry (HD) (38°C and 28% relative humidity) and hot and humid (HH) conditions (38°C and 64% relative humidity) at their common 10 km race-running rhythm. HRV and body mass were assessed pre- and post-trial; the rating of perceived exertion and HRV were assessed during the trial; and HRV measurements were repeated 2, 4, 8, and 24 h postexercise. Primary HRV outcomes were root mean square of the successive differences, high frequency power, stress score, and sympathetic/parasympathetic ratio. One-way analysis of variance testing was used to analyze differences. Results No significant difference in body mass occurred across the different conditions or distances covered (P>0.05). Rating of perceived exertion presented the highest correlation values with stress score (r=0.729 for HD; r=0.568 for HH) and sympathetic/parasympathetic ratio (r=0.621 for HD; r=0.519 for HH) during exercise. HRV recovered to baseline values more quickly after exercising under dry conditions (4 h) than under humid conditions (between 8 and 24 h). Conclusions Stress score and sympathetic/parasympathetic ratio seem to be the best HRV predictors of internal load. Although there are no differences in HRV during recovery at the same time points in both conditions, the recovery is slower after exercise in HH than in HD.