Delayed parasympathetic reactivation and sympathetic withdrawal following maximal cardiopulmonary exercise testing (CPET) in hypoxia

Alessandro Fornasiero, Aldo Savoldelli, Spyros Skafidas, Federico Stella, Lorenzo Bortolan, Gennaro Boccia, Andrea Zignoli, Federico Schena, Laurent Mourot, Barbara Pellegrini

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Purpose: This study investigated the effects of acute hypoxic exposure on post-exercise cardiac autonomic modulation following maximal cardiopulmonary exercise testing (CPET). Methods: Thirteen healthy men performed CPET and recovery in normoxia (N) and normobaric hypoxia (H) (FiO2 = 13.4%, ≈ 3500 m). Post-exercise cardiac autonomic modulation was assessed during recovery (300 s) through the analysis of fast-phase and slow-phase heart rate recovery (HRR) and heart rate variability (HRV) indices. Results: Both short-term, T30 (mean difference (MD) 60.0 s, 95% CI 18.2–101.8, p = 0.009, ES 1.01), and long-term, HRRt (MD 21.7 s, 95% CI 4.1–39.3, p = 0.020, ES 0.64), time constants of HRR were higher in H. Fast-phase (30 and 60 s) and slow-phase (300 s) HRR indices were reduced in H either when expressed in bpm or in percentage of HRpeak (p < 0.05). Chronotropic reserve recovery was lower in H than in N at 30 s (MD − 3.77%, 95% CI − 7.06 to − 0.49, p = 0.028, ES − 0.80) and at 60 s (MD − 7.23%, 95% CI − 11.45 to − 3.01, p = 0.003, ES − 0.81), but not at 300 s (p = 0.436). Concurrently, Ln-RMSSD was reduced in H at 60 and 90 s (p < 0.01) but not at other time points during recovery (p > 0.05). Conclusions: Affected fast-phase, slow-phase HRR and HRV indices suggested delayed parasympathetic reactivation and sympathetic withdrawal after maximal exercise in hypoxia. However, a similar cardiac autonomic recovery was re-established within 5 min after exercise cessation. These findings have several implications in cardiac autonomic recovery interpretation and in HR assessment in response to high-intensity hypoxic exercise.

Original languageEnglish
Pages (from-to)2189-2201
Number of pages13
JournalEuropean Journal of Applied Physiology
Volume118
Issue number10
DOIs
Publication statusPublished - 1 Oct 2018

Keywords

  • Cardiac autonomic activity
  • Heart rate recovery
  • Hypoxia
  • Hypoxic exercise
  • Post-exercise recovery

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Public Health, Environmental and Occupational Health
  • Physiology (medical)

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