PHYSIOLOGICAL RESPONSES TO HIGH INTENSITY INTERVALS ARE STRONGLY ASSOCIATED WITH W-PRIME DEPLETION IN NORMOXIA AND HYPOXIA

Abstract

The Critical Power (CP) model serves as a basis for exploring the interplay between work and recovery during high-intensity intermittent exercise (HIIE), utilizing Work-balance (W′BAL) models. Central to this framework is W′ or W-prime, a finite reserve of work capacity above CP, whose depletion and recovery kinetics are influenced by physiological mechanisms associated with non-steady state oxidative metabolism This study aims to examine the differences among four W′BAL models under normoxic and hypoxic conditions at states of partial and complete depletion and to evaluate the relationship between physiological parameters and W′BAL depletion during HIIE. Methods: Re-analysis of pre-existing data from an earlier study conducted in 2017. The HIIE protocol included 9 work-recovery intervals and a 3-minute time trial. Linear mixed modeling was conducted to compute the effect of various W′BAL models and environmental conditions on the relationship between W depletion and physiological responses. Results: Significant differences were observed between W′BAL models during states of partial depletion. A strong positive relationship was identified between W′ depletion and progressively increasing V̇O2, V̇E, and HR responses (p < 0.001). No significant effect of hypoxia was observed. Conclusion: These findings are consistent with the theory that a mechanistic link between W′, V̇O2SC, and peripheral muscle fatigue exists as inferred by the strong relationship with non-steady state VO2 kinetics. Furthermore, the present study indicates that W′BAL at partial levels of depletion and recovery reflects the magnitude of VO2 slow component during HIIE. Therefore, W′BAL could (or should) be conceptualized as a mathematical description of fatigue.accumulation.and recovery, as opposed to anaerobic energy depletion and recovery.

Date of Award	2024
Original language	American English
Awarding Institution	HBKU College of Health & Life Sciences