Health, Exercise, and Sports Sciences ETDs

Publication Date

9-12-2014

Abstract

Reduced partial pressure of oxygen impairs exercise performance at altitude. Acute nitrate supplementation, at sea level may reduce oxygen cost during submaximal exercise in hypoxia. Therefore, we investigated the metabolic response during exercise at altitude following acute nitrate consumption. Ten well-trained (61.01±7.37 ml/kg/min) males (age 28±7 yr) completed 3 experimental trials (T1, T2, T3). T1 included baseline demographics, a maximal aerobic capacity test (VO2max) and five submaximal intensity cycling determination bouts at an elevation of 1600m. A 4-day dietary washout, minimizing consumption of nitrate rich foods, preceded T2 and T3. In a randomized, double-blind, placebo-controlled, crossover fashion, subjects consumed a placebo (PL) or nitrate rich (NR) beverage 2.5 hours prior to T2 and T3. Exercise at 3500m (T2 and T3) consisted of a 5-min warm-up (25% VO2max) and four 5-min cycling bouts (40, 50, 60, 70% of VO2max) each separated a 4-min rest period. Cycling RPM and watts for each submaximal bout were determined during T1. Pre-exercise plasma nitrite was elevated following NR consumption compared to PL (p<0.05). Oxygen consumption, respiratory exchange ratio, oxygen saturation, heart rate and rating of perceived exertion were not different at any submaximal intensity between NR and PL treatments. Blood lactate, however, was reduced following NR consumption compared to PL at 40 and 60% of VO2max (p<.0.05). Following exercise, compared to rest, catalase and 8-isoprostane increased at 3500m in both the placebo and nitrate rich groups (p<0.05). There was no difference between groups (placebo vs nitrate rich) for either of these markers of oxidative stress. Our findings suggest that acute nitrate supplementation prior to exercise at 3500m does not reduce oxygen cost or oxidative stress, but may reduce lactate production at lower intensity workloads.

Keywords

Nitrate

Sponsors

University of New Mexico - College of Education

Document Type

Dissertation

Language

English

Degree Name

Physical Education, Sports and Exercise Science

Level of Degree

Doctoral

Department Name

Health, Exercise, and Sports Sciences

First Committee Member (Chair)

Vaughan, Roger

Second Committee Member

Witt, Christopher

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