Journal article
Repeated Ischemic Preconditioning Effects on Physiological Responses to Hypoxic Exercise
Aerospace Medicine and Human Performance, Vol.93(1), pp.13-21
2022
PMID: 35063051
Abstract
INTRODUCTION: Repeated ischemic preconditioning (IPC) can improve muscle and pulmonary oxygen on-kinetics, blood flow, and exercise efficiency, but these effects have not been investigated in severe hypoxia. The aim of the current study was to evaluate the effects of 7 d of IPC on resting and exercising muscle and cardio-pulmonary responses to severe hypoxia.
METHODS: A total of 14 subjects received either: 1) 7 d of repeated lower-limb occlusion (4 × 5 min, 217 ± 30 mmHg) at limb occlusive pressure (IPC) or SHAM (4 × 5 min, 20 mmHg). Subjects were tested for resting limb blood flow, relative microvascular deoxyhemoglobin concentration ([HHB]), and pulmonary oxygen (Vo2p) responses to steady state and incremental exercise to exhaustion in hypoxia (fractional inspired O2 = 0.103), which was followed by 7 d of IPC or SHAM and retesting 72 h post-intervention.
RESULTS: There were no effects of IPC on maximal oxygen consumption, time to exhaustion during the incremental test, or minute ventilation and arterial oxygen saturation. However, the IPC group had higher delta efficiency based on pooled results and lower steady state Δ[HHB] (IPC ∼24% vs. SHAM ∼6% pre to post), as well as slowing the [HHB] time constant (IPC ∼26% vs. SHAM ∼3% pre to post) and reducing the overshoot in [HHB]: Vo2 ratio during exercise onset.
CONCLUSIONS: Collectively, these results demonstrate that muscle O2 efficiency and microvascular O2 distribution can be improved by repeated IPC, but there are no effects on maximal exercise capacity in severe hypoxia.
Details
- Title
- Repeated Ischemic Preconditioning Effects on Physiological Responses to Hypoxic Exercise
- Authors
- Kiran Chopra (Author) - St Mary's University Twickenham LondonOwen Jeffries (Author) - Newcastle UniversityJamie Tallent (Author) - University of EssexShane Heffernan (Author) - University of EssexLiam Kilduff (Author) - Swansea UniversityAdrian Gray (Author) - University of the Sunshine Coast, Queensland, School of Health and Behavioural Sciences - LegacyMark Waldron (Author) - University of the Sunshine Coast, Queensland, School of Health and Behavioural Sciences - Legacy
- Publication details
- Aerospace Medicine and Human Performance, Vol.93(1), pp.13-21
- Publisher
- Aerospace Medical Association
- DOI
- 10.3357/AMHP.5919.2022
- ISSN
- 2375-6322
- PMID
- 35063051
- Organisation Unit
- School of Health and Behavioural Sciences - Legacy; University of the Sunshine Coast, Queensland
- Language
- English
- Record Identifier
- 99622937802621
- Output Type
- Journal article
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