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Hyperbaric oxygenation reduces exercising forearm blood flow in humans
Author(s) -
Casey Darren P.,
Joyner Michael J.,
Claus Paul L.,
Bigelow Maureen L.,
Fuqua William R.,
Balgeman Jon R.,
Curry Timothy B.
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.1023.1
Subject(s) - hyperoxia , medicine , supine position , forearm , blood flow , anesthesia , vasodilation , hypoxia (environmental) , reactive hyperemia , brachial artery , cardiology , skeletal muscle , oxygenation , blood pressure , chemistry , oxygen , surgery , lung , organic chemistry
Hypoxia during exercise augments vasodilation and blood flow to ensure adequate delivery of O 2 to active muscles. However, the impact of hyperoxia on skeletal muscle blood flow during exercise is poorly understood. Therefore, we tested the hypothesis that the hyperemic response to exercise with hyperbaric hyperoxia would be blunted compared to exercise during normoxia. Seven subjects (6M/1F; 26 ± 2 years) performed forearm exercise (20% of maximum) under normoxic and hyperoxic conditions. Forearm blood flow (FBF; ml/min) was measured using Doppler ultrasound. Forearm vascular conductance (FVC; ml/min/100mmHg) was calculated from FBF and blood pressure (mmHg; brachial arterial catheter). Studies were performed in a hyperbaric chamber with the subjects supine at 1 ATA (sea level) and 2.8 ATA while breathing normoxic (21% O 2 , 1 ATA; F I O 2 ≈ 150 mmHg), hyperbaric normoxic (7% O 2 , 2.8 ATA, F I O 2 ≈ 150 mmHg) and hyperoxic (7% O 2 , 2.8 ATA, F I O 2 ≈ 2100 mmHg) gas. The change in FBF and FVC (Δ from rest) during exercise under normoxia and hyperbaric normoxia did not differ (P > 0.05). However, the ΔFBF and ΔFVC during exercise under hyperoxia were attenuated by ~18–29% compared to both normoxic conditions (P ≤ 0.01). Our data suggest that exercise hyperemia in skeletal muscle is highly dependent on oxygen availability during hyperoxia as well as hypoxia. NIH HL46493 (MJJ), AR55819 (DPC) and RR‐024150.