摘要
BESCOS, R., F. A. RODRIGUEZ, X. IGLESIAS, M. D. FERRER, E. IBORRA, and A. PONS. Acute Administration of Inorganic Nitrate Reduces (V) over dotO(2peak) in Endurance Athletes. Med. Sci. Sports Exerc., Vol. 43, No. 10, pp. 1979-1986, 2011. Purpose: Humans can reduce inorganic nitrate (NO3-) to nitrite (NO2-), nitric oxide (NO), and other bioactive nitrogen oxides. The purpose of this study was to test the hypothesis that a single dose of inorganic nitrate before exercise might enhance the tolerance of endurance athletes to high intensity exercise. Methods: Eleven cyclists (age = 34.3 +/- 4.8 yr, (V) over dotO(2peak) = 65.1 +/- 6.2 mL.kg(-1).min(-1)) participated in this randomized, double-blind, crossover study. Subjects received dietary supplementation with nitrate (NaNO3 10 mg.kg(-1) of body mass) or a placebo (NaCl) 3 h before exercise. They then performed a cycle ergometer test that consisted of four 6-min submaximal workloads, corresponding to 2.0, 2.5, 3.0, and 3.5 W.kg(-1) of body mass, interspersed with 3 min of passive recovery. After a 5-min recovery period, subjects performed one incremental exercise test until exhaustion. Results: Plasma nitrate and nitrite were significantly higher (P < 0.05) 3 h after supplementation (nitrate = 250 +/- 80 mu M, nitrite = 2313 +/- 157 nM) than after the placebo (nitrate = 29 +/- 8 mu M, nitrite = 1998 +/- 206 nM) at resting conditions. Nitrate supplementation significantly reduced (V) over dotO(2peak) (nitrate = 4.64 +/- 0.35 L.min(-1), placebo = 4.82 +/- 0.33 L.min(-1), P = 0.010) and the ratio between (V) over dotO(2) and power at maximal intensity (nitrate = 11.2 +/- 1.1 mL.min(-1).W-1, placebo = 11.8 +/- 1.1 mL.min(-1).W-1, P = 0.031). This reduction of (V) over dotO(2) occurred without changes in the time to exhaustion (nitrate = 416 +/- 32 s, placebo = 409 +/- 27 s) or in the maximal power (nitrate = 416 +/- 29 W, placebo = 410 +/- 28 W). Conclusions: A single oral dose of inorganic nitrate acutely reduces (V) over dotO(2peak) without compromising the maximal exercise performance.
- 出版日期2011-10