NO3- supplementation via beetroot juice (BR) augments exercising skeletal muscle blood flow subsequent to its reduction to NO2- then NO. We tested the hypothesis that enhanced vascular control following BR would elevate the skeletal muscle O2 delivery/O2 utilization ratio (microvascular PO2, PmvO2) and raise the PmvO2 during the rest-contractions transition. Rats were administered BR (~0.8mmol/kg/day, n=10) or water (control, n=10) for 5 days. PmvO2 was measured during 180s of electrically induced (1Hz) twitch spinotrapezius muscle contractions. There were no changes in resting or contracting steady-state PmvO2. However, BR slowed the PmvO2 fall following contractions onset such that time to reach 63% of the initial PmvO2 fall increased (MRT1; control: 16.8±1.9, BR: 24.4±2.7s, p<0.05) and there was a slower relative rate of PmvO2 fall (δ1PmvO2/τ1; control: 1.9±0.3, BR: 1.2±0.2mmHg/s, p<0.05). Despite no significant changes in contracting steady state PmvO2, BR supplementation elevated the O2 driving pressure during the crucial rest-contractions transients thereby providing a potential mechanism by which BR supplementation may improve metabolic control. © 2013 Elsevier B.V.
CITATION STYLE
Ferguson, S. K., Hirai, D. M., Copp, S. W., Holdsworth, C. T., Allen, J. D., Jones, A. M., … Poole, D. C. (2013). Effects of nitrate supplementation via beetroot juice on contracting rat skeletal muscle microvascular oxygen pressure dynamics. Respiratory Physiology and Neurobiology, 187(3), 250–255. https://doi.org/10.1016/j.resp.2013.04.001
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