A Randomized Controlled Trial Of Nitrate Supplementation In Well-Trained Middle And Older-Aged Adults

PurposeNitrate (NO3-), through its conversion to nitrite (NO2-) and nitric oxide, has been shown to increase exercise tolerance in healthy younger adults and older diseased patients. Nitrate's effect in well-trained middle to older-aged adults has not been studied. Therefore, the purpose of this investigation was to examine the effects of a NO(3)(-)rich beverage on submaximal constant work rate exercise time in well-trained middle to older-aged adults.MethodsThis was a randomized controlled cross-over trial with 15 well-trained middle to older-aged adults, 41-64 year-old, who received one of two treatments (NO(3)(-)rich beverage then placebo or placebo then NO(3)(-)rich beverage), after which an exercise test at 75 percent of the subject's maximal work rate was completed.ResultsThe NO(3)(-)rich beverage increased plasma NO(3)(-)and NO(2)(-)levels by 260 mu M and 0.47 mu M, respectively (p<0.001). Exercise time was not significantly different (p = 0.31) between the NO(3)(-)rich versus placebo conditions (1130 +/- 151 vs 1060 +/- 132 sec, respectively). Changes in exercise time between the two conditions ranged from a 55% improvement to a 40% decrease with the NO(3)(-)rich beverage. Oxygen consumption and rating of perceived exertion were not significantly different between the two conditions.ConclusionIn middle to older-aged well-trained adults, NO(3)(-)supplementation has non-significant, albeit highly variable, effects on exercise tolerance.