Skip to main content
main-content

10.11.2017 | Original Article | Ausgabe 1/2018 Open Access

European Journal of Applied Physiology 1/2018

Heart rate variability and plasma nephrines in the evaluation of heat acclimatisation status

Zeitschrift:
European Journal of Applied Physiology > Ausgabe 1/2018
Autoren:
Major Michael John Stacey, S. K. Delves, D. R. Woods, S. E. Britland, L. Macconnachie, A. J. Allsopp, S. J. Brett, J. L. Fallowfield, C. J. Boos
Wichtige Hinweise
Communicated by Narihiko Kondo.

Electronic supplementary material

The online version of this article (https://​doi.​org/​10.​1007/​s00421-017-3758-y) contains supplementary material, which is available to authorized users.

Abstract

Purpose

Heat adaptation (HA) is critical to performance and health in a hot environment. Transition from short-term heat acclimatisation (STHA) to long-term heat acclimatisation (LTHA) is characterised by decreased autonomic disturbance and increased protection from thermal injury. A standard heat tolerance test (HTT) is recommended for validating exercise performance status, but any role in distinguishing STHA from LTHA is unreported. The aims of this study were to (1) define performance status by serial HTT during structured natural HA, (2) evaluate surrogate markers of autonomic activation, including heart rate variability (HRV), in relation to HA status.

Methods

Participants (n = 13) were assessed by HTT (60-min block-stepping, 50% VO2peak) during STHA (Day 2, 6 and 9) and LTHA (Day 23). Core temperature (Tc) and heart rate (HR) were measured every 5 min. Sampling for HRV indices (RMSSD, LF:HF) and sympathoadrenal blood measures (cortisol, nephrines) was undertaken before and after (POST) each HTT.

Results

Significant (P < 0.05) interactions existed for Tc, logLF:HF, cortisol and nephrines (two-way ANOVA; HTT by Day). Relative to LTHA, POST results differed significantly for Tc (Day 2, 6 and 9), HR (Day 2), logRMSSD (Day 2 and Day 6), logLF:HF (Day 2 and Day 6), cortisol (Day 2) and nephrines (Day 2 and Day 9). POST differences in HRV (Day 6 vs. 23) were + 9.9% (logRMSSD) and − 18.6% (logLF:HF).

Conclusions

Early reductions in HR and cortisol characterised STHA, whereas LTHA showed diminished excitability by Tc, HRV and nephrine measures. Measurement of HRV may have potential to aid real-time assessment of readiness for activity in the heat.

Unsere Produktempfehlungen

e.Med Interdisziplinär

Kombi-Abonnement

Mit e.Med Interdisziplinär erhalten Sie Zugang zu allen CME-Fortbildungen und Fachzeitschriften auf SpringerMedizin.de. Zusätzlich können Sie eine Zeitschrift Ihrer Wahl in gedruckter Form beziehen – ohne Aufpreis.

e.Med Allgemeinmedizin

Kombi-Abonnement

Mit e.Med Allgemeinmedizin erhalten Sie Zugang zu allen CME-Fortbildungen und Premium-Inhalten der allgemeinmedizinischen Zeitschriften, inklusive einer gedruckten Allgemeinmedizin-Zeitschrift Ihrer Wahl.​​​​​​​​​​​​​​

Zusatzmaterial
Supplemental Material 1. (DOCX 16 KB)
421_2017_3758_MOESM1_ESM.docx
Literatur
Über diesen Artikel

Weitere Artikel der Ausgabe 1/2018

European Journal of Applied Physiology 1/2018 Zur Ausgabe

Neu im Fachgebiet Arbeitsmedizin