Dietary nitrate (NO3-) supplementation serves as an exogenous source of nitrite (NO2-) and nitric oxide (NO) through the NO3- - NO2- - NO pathway, and may improve vascular functions during normoxia. The effects of NO3- supplementation in healthy lowlanders during hypobaric hypoxia are unknown.Determine the effect of acute oral NO3-supplementation via beetroot juice (BJ) on endothelial function (flow mediated dilation; FMD) in lowlanders at 3700 m.FMD was measured using ultrasound and Doppler in the brachial artery of 11 healthy subjects (4 females, age 25 ± 5 yrs; height 1.8 ± 0.1 m, weight 72 ± 10 kg) sojourning to high altitude. In a randomized, double-blinded crossover study design, FMD was measured 3 h after drinking BJ (5.0 mmol NO3-) and placebo (PL; 0.003 mmol NO3-) supplementation at 3700 m, with a 24-h wash out period between tests. FMD was also measured without any BJ supplementation pre-trek at 1370 m, after 5 days at 4200 m and upon return to 1370 m after 4 weeks of altitude exposure (above 2500 m). The altitude exposure was interrupted by a decent to lower altitude where subjects spent two nights at 1370 m before returning to altitude again.Ten subjects completed the NO3- supplementation. FMD (mean ± SD) pre-trek value was 6.53 ± 2.32

作者：Emily, Bakker；Harald, Engan；Alexander, Patrician；Erika, Schagatay；Trine, Karlsen；Ulrik, Wisl?ff；Svein Erik, Gaustad

来源：Nitric oxide : biology and chemistry 2015 年 50卷