Influence of acute dietary nitrate supplementation on oxygen delivery/consumption and limit of tolerance during progressive forearm exercise in men: a randomized crossover trial.

Autor: Fenuta AM; School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada., Drouin PJ; School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada., Kohoko ZIN; School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada., Lynn MJT; School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada., Tschakovsky ME; School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada.
Jazyk: angličtina
Zdroj: Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme [Appl Physiol Nutr Metab] 2024 May 01; Vol. 49 (5), pp. 635-648. Date of Electronic Publication: 2024 Jan 08.
DOI: 10.1139/apnm-2023-0236
Abstrakt: Beetroot juice (BRJ) supplementation increases nitric oxide bioavailability with hypoxia and acidosis, characteristics of high-intensity exercise. We investigated whether BRJ improved forearm oxygen delivery:demand matching in an intensity-dependent manner. Healthy men (21 ± 2.5 years) participated in a randomized crossover trial between October 2017 and May 2018 (Queen's University, Kingston, ON, Canada). Participants completed a forearm incremental exercise test to limit of tolerance (IET-LOT) 2.5 h post placebo (PL) versus BRJ (2 completed PL/BRJ vs. 9 completed BRJ/PL) within a 2-week period. Data are presented as mean ± standard deviation. There was a significant main effect of drink (PL < BRJ; P  = 0.042, η p 2  = 0.385) and drink × intensity interaction for arteriovenous oxygen difference (PL < BRJ; P  = 0.03; η p 2 = 0.197; 20%-50% and 90% LOT). BRJ did not influence oxygen delivery ( P  = 0.893, η p 2  = 0.002), forearm blood flow ( P  = 0.589, η p 2  = 0.03) (forearm vascular conductance ( P  = 0.262, η p 2  = 0.124), mean arterial pressure ( P  = 0.254,η p 2  = 0.128)), oxygen consumption ( P  = 0.194, η p 2  = 0.179) or LOT ( P  = 0.432, d  = 0.247). In healthy men, BRJ did not improve forearm oxygen delivery (vasodilatory or pressor response) during IET-LOT. Increased arteriovenous oxygen difference at submaximal intensities did not significantly influence oxygen consumption or performance across the entire range of forearm exercise intensities. This study adds to the growing body of evidence that BRJ does not influence small muscle mass blood flow in humans regardless of exercise intensity.
Competing Interests: The authors declare there are no competing interests.
Databáze: MEDLINE
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