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Passive Heating Attenuates Post-exercise Cardiac Autonomic Recovery in Healthy Young Males

Post-exercise heart rate (HR) recovery (HRR) presents a biphasic pattern, which is mediated by parasympathetic reactivation and sympathetic withdrawal. Several mechanisms regulate these post-exercise autonomic responses and thermoregulation has been proposed to play an important role. The aim of thi...

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Autores principales: Peçanha, Tiago, Forjaz, Cláudia L. de Moraes, Low, David A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5742592/
https://www.ncbi.nlm.nih.gov/pubmed/29311799
http://dx.doi.org/10.3389/fnins.2017.00727
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author Peçanha, Tiago
Forjaz, Cláudia L. de Moraes
Low, David A.
author_facet Peçanha, Tiago
Forjaz, Cláudia L. de Moraes
Low, David A.
author_sort Peçanha, Tiago
collection PubMed
description Post-exercise heart rate (HR) recovery (HRR) presents a biphasic pattern, which is mediated by parasympathetic reactivation and sympathetic withdrawal. Several mechanisms regulate these post-exercise autonomic responses and thermoregulation has been proposed to play an important role. The aim of this study was to test the effects of heat stress on HRR and HR variability (HRV) after aerobic exercise in healthy subjects. Twelve healthy males (25 ± 1 years, 23.8 ± 0.5 kg/m(2)) performed 14 min of moderate-intensity cycling exercise (40–60% HR(reserve)) followed by 5 min of loadless active recovery in two conditions: heat stress (HS) and normothermia (NT). In HS, subjects dressed in a whole-body water-perfused tube-lined suit to increase internal temperature (T(c)) by ~1°C. In NT, subjects did not wear the suit. HR, core and skin temperatures (T(c) and T(sk)), mean arterial pressure (MAP) skin blood flow (SKBF), and cutaneous vascular conductance (CVC) were measured throughout and analyzed during post-exercise recovery. HRR was assessed through calculations of HR decay after 60 and 300 s of recovery (HRR60s and HRR300s), and the short- and long-term time constants of HRR (T30 and HRRt). Post-exercise HRV was examined via calculations of RMSSD (root mean square of successive RR intervals) and RMS (root mean square residual of RR intervals). The HS protocol promoted significant thermal stress and hemodynamic adjustments during the recovery (HS-NT differences: T(c) = +0.7 ± 0.3°C; T(sk) = +3.2 ± 1.5°C; MAP = −12 ± 14 mmHg; SKBF = +90 ± 80 a.u; CVC = +1.5 ± 1.3 a.u./mmHg). HRR and post-exercise HRV were significantly delayed in HS (e.g., HRR60s = 27 ± 9 vs. 44 ± 12 bpm, P < 0.01; HRR300s = 39 ± 12 vs. 59 ± 16 bpm, P < 0.01). The effects of heat stress (e.g., the HS-NT differences) on HRR were associated with its effects on thermal and hemodynamic responses. In conclusion, heat stress delays HRR, and this effect seems to be mediated by an attenuated parasympathetic reactivation and sympathetic withdrawal after exercise. In addition, the impact of heat stress on HRR is related to the magnitude of the heat stress-induced thermal stress and hemodynamic changes.
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spelling pubmed-57425922018-01-08 Passive Heating Attenuates Post-exercise Cardiac Autonomic Recovery in Healthy Young Males Peçanha, Tiago Forjaz, Cláudia L. de Moraes Low, David A. Front Neurosci Neuroscience Post-exercise heart rate (HR) recovery (HRR) presents a biphasic pattern, which is mediated by parasympathetic reactivation and sympathetic withdrawal. Several mechanisms regulate these post-exercise autonomic responses and thermoregulation has been proposed to play an important role. The aim of this study was to test the effects of heat stress on HRR and HR variability (HRV) after aerobic exercise in healthy subjects. Twelve healthy males (25 ± 1 years, 23.8 ± 0.5 kg/m(2)) performed 14 min of moderate-intensity cycling exercise (40–60% HR(reserve)) followed by 5 min of loadless active recovery in two conditions: heat stress (HS) and normothermia (NT). In HS, subjects dressed in a whole-body water-perfused tube-lined suit to increase internal temperature (T(c)) by ~1°C. In NT, subjects did not wear the suit. HR, core and skin temperatures (T(c) and T(sk)), mean arterial pressure (MAP) skin blood flow (SKBF), and cutaneous vascular conductance (CVC) were measured throughout and analyzed during post-exercise recovery. HRR was assessed through calculations of HR decay after 60 and 300 s of recovery (HRR60s and HRR300s), and the short- and long-term time constants of HRR (T30 and HRRt). Post-exercise HRV was examined via calculations of RMSSD (root mean square of successive RR intervals) and RMS (root mean square residual of RR intervals). The HS protocol promoted significant thermal stress and hemodynamic adjustments during the recovery (HS-NT differences: T(c) = +0.7 ± 0.3°C; T(sk) = +3.2 ± 1.5°C; MAP = −12 ± 14 mmHg; SKBF = +90 ± 80 a.u; CVC = +1.5 ± 1.3 a.u./mmHg). HRR and post-exercise HRV were significantly delayed in HS (e.g., HRR60s = 27 ± 9 vs. 44 ± 12 bpm, P < 0.01; HRR300s = 39 ± 12 vs. 59 ± 16 bpm, P < 0.01). The effects of heat stress (e.g., the HS-NT differences) on HRR were associated with its effects on thermal and hemodynamic responses. In conclusion, heat stress delays HRR, and this effect seems to be mediated by an attenuated parasympathetic reactivation and sympathetic withdrawal after exercise. In addition, the impact of heat stress on HRR is related to the magnitude of the heat stress-induced thermal stress and hemodynamic changes. Frontiers Media S.A. 2017-12-21 /pmc/articles/PMC5742592/ /pubmed/29311799 http://dx.doi.org/10.3389/fnins.2017.00727 Text en Copyright © 2017 Peçanha, Forjaz and Low. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Neuroscience
Peçanha, Tiago
Forjaz, Cláudia L. de Moraes
Low, David A.
Passive Heating Attenuates Post-exercise Cardiac Autonomic Recovery in Healthy Young Males
title Passive Heating Attenuates Post-exercise Cardiac Autonomic Recovery in Healthy Young Males
title_full Passive Heating Attenuates Post-exercise Cardiac Autonomic Recovery in Healthy Young Males
title_fullStr Passive Heating Attenuates Post-exercise Cardiac Autonomic Recovery in Healthy Young Males
title_full_unstemmed Passive Heating Attenuates Post-exercise Cardiac Autonomic Recovery in Healthy Young Males
title_short Passive Heating Attenuates Post-exercise Cardiac Autonomic Recovery in Healthy Young Males
title_sort passive heating attenuates post-exercise cardiac autonomic recovery in healthy young males
topic Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5742592/
https://www.ncbi.nlm.nih.gov/pubmed/29311799
http://dx.doi.org/10.3389/fnins.2017.00727
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