Examining the acute cardiovagal consequences of supine recovery during high-intensity interval exercise

John P Sasso; Kyla Coates; Liam Stewart; Jinelle Gelinas; Stephen P Wright; Stephen Seiler; Robert Shave; Neil D Eves

doi:10.1007/s00421-024-05641-w

Examining the acute cardiovagal consequences of supine recovery during high-intensity interval exercise

Eur J Appl Physiol. 2024 Oct 23. doi: 10.1007/s00421-024-05641-w. Online ahead of print.

Authors

John P Sasso¹, Kyla Coates¹, Liam Stewart¹, Jinelle Gelinas¹, Stephen P Wright¹, Stephen Seiler², Robert Shave¹, Neil D Eves³

Affiliations

¹ School of Health and Exercise Sciences, University of British Columbia, 1147 Research Road, Kelowna, BC, V1V 1V7, Canada.
² Faculty of Health and Sport Sciences, University of Agder, Kristiansand, Norway.
³ School of Health and Exercise Sciences, University of British Columbia, 1147 Research Road, Kelowna, BC, V1V 1V7, Canada. neil.eves@ubc.ca.

PMID: 39441381
DOI: 10.1007/s00421-024-05641-w

Abstract

Purpose: Exercise training requires the careful application of training dose to maximize adaptation while minimizing the risk of illness and injury. High-intensity interval training (HIIT) is a potent method for improving health and fitness but generates substantial autonomic imbalance. Assuming a supine posture between intervals is a novel strategy that could enhance physiological readiness and training adaptations. This study aimed to establish the safety and feasibility of supine recovery within a HIIT session and explore its acute effects.

Methods: Fifteen healthy, active males (18-34 years) underwent assessment of cardiopulmonary fitness. Participants completed two identical HIIT treadmill sessions (4 x [3 min at 95% VO_2max, 3 min recovery]) employing passive recovery in standing (STANDard) or supine (SUPER) posture between intervals. Heart rate variability (HRV), HRV recovery (HRVrec; lnRMSSD) and heart rate recovery at 1 min (HRrec) were assessed using submaximal constant speed running tests (CST) completed prior to, immediately after and 24 h following HIIT.

Results: No severe adverse events occurred with SUPER, and compliance was similar between conditions (100 ± 0%). The change in HRVrec from the CST pre-to-post-HIIT was not different between conditions (p = 0.38); however, HRrec was faster following SUPER (39 ± 7 bpm) vs. STANDard (36 ± 5 bpm). HRV 24 h post-SUPER was also greater (3.56 ± 0.57 ms) compared to STANDard (3.37 ± 0.42 ms). Despite no differences in perceived exertion (p = 0.23) and blood lactate levels (p = 0.35) between SUPER and STANDard, average running HRs were lower (p = 0.04) with SUPER (174 ± 7 bpm) vs. STANDard (176 ± 7 bpm).

Conclusions: Supine recovery within HIIT attenuates acute cardioautonomic perturbation and accelerates post-exercise vagal reactivation. SUPER enhances recovery of vagal modulation, potentially improving physiological preparedness 24 h post-HIIT. Further research exploring the chronic effects of SUPER are now warranted.

Keywords: Autonomic nervous system; Cardioautonomic status; Heart rate recovery; Heart rate variability; High intensity interval training; Parasympathetic reactivation; Vagal tone.