Acute Dietary Nitrate Supplementation Does Not Attenuate Oxidative Stress or the Hemodynamic Response During Submaximal Exercise in Hypobaric Hypoxia

Purpose: To investigate changes in oxidative stress, arterial oxygen saturation (SaO2), blood pressure (BP), and heart rate (HR) while exercising in hypobaric hypoxia following acute dietary nitrate supplementation. Methods: Nine well-trained (60.8±7.8 ml/kg/min) males (29±7 years) visited the lab on 3 occasions, each separated by 1 week. Visit 1 included a maximal aerobic cycling test (VO2max) and 5 five-minute increasing intensity exercise bouts in a normobaric environment (1600m). A single dose of either a nitrate-depleted placebo (PL) or nitrate-rich (NR; 12.8 mmol nitrate) beverage was consumed 2.5 hours prior to exercise during visit 2 and 3 (3500m) in a double-blind, placebo-controlled, crossover study consisting of a 5-minute cycling warm-up and four bouts, each of 5-minute durations, separated by 4-minute periods of passive rest. Exercise wattages were determined during visit 1 and corresponded to 25, 40, 50, 60, 70% of normobaric VO2max. Catalase and 8 isoprostane were measured pre-exercise and post-exercise (immediately and 1-hour post-exercise, respectively). Results: Dietary nitrate increased plasma nitrite (1.53±0.83 uM) compared to PL (0.88±0.56 uM) (pThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author