Fluid Replacement Strategies and Heart Rate Variability Recovery Following Prolonged Exercise in the Heat and Mild Dehydration
Abstract
Background: In sporting and combat settings, optimal fluid replacement is rarely achieved, exacerbating physiological strain. It is unknown if prescribed fluid replacement following exercise in heat impacts heart rate variability (HRV). Purpose: Compare prescribed drinking (PD) and ad libitum (AL) fluid replacement on HRV following exercise in heat. Methods: Twelve participants (26 ± 5 years, VO2max: 58.44 ± 7.05 mL·kg−1·min−1) completed three trials in heat (36 °C, 36% humidity) on separate days, and were placed into groups, PD or AL. Recovery was assessed ~24 h later (hydration and HRV). HRV time and frequency was measured using a 3-lead electrocardiogram. Two-way repeated measures analysis of variance measured changes in HRV pre-trial, post-trial, and follow-up between groups. Data reported: p-value, mean difference (MD). Results: Fluid consumption was greater in PD during recovery (p = 0.012, MD = 1245 mL). Both groups were euhydrated at follow-up. HRV time (p 0.05). Conclusions: Replacing ≥60% fluid sufficiently rehydrates and restores HRV 24 h post-exercise in heat and mild dehydration (BML ≤ 3%). Prescribed fluid consumption during recovery was ~30% greater. Additional measures of recovery sensitive to heat strain may provide a more holistic understanding of specific mechanisms of recovery.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 16, 2023
- Source ID
- 10.3390/physiologia3010008
Entities
People
- Ciara N. Manning
- Douglas J. Casa
- Jaques Reifman
- Margaret C. Morrissey
- Rebecca L. Stearns
- Robert A. Huggins
- Ryan M. Curtis
- S. Laxminarayan
- Sean P. Langan
- Yasuki Sekiguchi
Organizations
- Henry M. Jackson Foundation for the Advancement of Military Medicine
- Texas Tech University
- United States Department of Defense
- University of Connecticut