Dietary nitrate reduces maximal oxygen consumption while maintaining work performance in maximal exercise
Dietary nitrate reduces maximal oxygen consumption while maintaining work performance in maximal exercise
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DOI：
10.1016/j.freeradbiomed.2009.11.006
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发表时间：
2010-01-15
影响因子：
7.4
通讯作者：
Ekblom, Bjorn
中科院分区：
文献类型：
--
作者：
Larsen, Filip J.;Weitzberg, Eddie;Ekblom, Bjorn
在我们的饮食中丰富的阴离子硝酸盐，最近出现作为一个主要的池一氧化氮（NO）的脱氢酶独立的NO生产。硝酸盐在体内逐步还原为亚硝酸盐，然后是NO和可能的其他生物活性氮氧化物。这种还原途径在低氧张力和酸中毒期间增强。最近的一项研究表明，在亚极量运动期间，膳食硝酸盐可导致耗氧量降低。我们继续研究膳食硝酸盐对极量运动期间各种生理和生化参数的影响。9名健康、不吸烟的志愿者（年龄30 +/- 2.3岁，VO 2 max 3.72 +/- 0.33 L/min）参加了本研究，该研究采用随机、双盲交叉设计。受试者在试验前2天接受硝酸钠（0.1 mmol/kg/天）或安慰剂（NaCl）的饮食补充。该剂量相当于100-300 g富含硝酸盐的蔬菜（如菠菜或甜菜根）中的含量。最大运动试验包括在两个单独的测力计上进行手臂和腿部联合摇动的递增运动至力竭。膳食硝酸盐使最大摄氧量从3.72 +/- 0.33降至3.62 +/- 0.31 L/min，P < 0.05。尽管最大摄氧量降低，但补充硝酸盐后至力竭的时间有增加的趋势（524 +/- 31 vs 563 +/- 30 s，P = 0.13）。运动至力竭时间的变化与最大摄氧量的变化相关（R-2 = 0.47，P = 0.04）。中等剂量的硝酸盐饮食显着降低VO 2 max在最大运动使用大的活动肌肉质量。这种减少的发生有一种增加疲劳时间的趋势，这意味着涉及两种不同的机制：一种是减少VO 2 max，另一种是改善工作肌肉的能量功能。(C)2009 Elsevier Inc. All rights reserved.
The anion nitrate-abundant in our diet-has recently emerged as a major pool of nitric oxide (NO) synthase-independent NO production. Nitrate is reduced stepwise in vivo to nitrite and then NO and possibly other bioactive nitrogen oxides. This reductive pathway is enhanced during low oxygen tension and acidosis. A recent study shows a reduction in oxygen consumption during submaximal exercise attributable to dietary nitrate, We went on to study the effects of dietary nitrate on various physiological and biochemical parameters during maximal exercise. Nine healthy, nonsmoking volunteers (age 30 +/- 2.3 years, VO2max 3.72 +/- 0.33 L/min) participated in this study, which had a randomized, double-blind crossover design. Subjects received dietary supplementation with sodium nitrate (0.1 mmol/kg/day) or placebo (NaCl) for 2 days before the test. This dose corresponds to the amount found in 100-300 g of a nitrate-rich vegetable such as spinach or beetroot. The maximal exercise tests consisted of an incremental exercise to exhaustion with combined arm and leg cranking on two separate ergometers. Dietary nitrate reduced VO2max from 3.72 +/- 0.33 to 3.62 +/- 0.31 L/min, P < 0.05. Despite the reduction in VO2max the time to exhaustion trended to an increase after nitrate supplementation (524 +/- 31 vs 563 +/- 30 s, P = 0.13). There was a correlation between the change in time to exhaustion and the change in VO2max (R-2 = 0.47, P = 0.04). A moderate dietary dose of nitrate significantly reduces VO2max during maximal exercise using a large active muscle mass. This reduction occurred with a trend toward increased time to exhaustion implying that two separate mechanisms are involved: one that reduces VO2max and another that improves the energetic function of the working muscles. (C) 2009 Elsevier Inc. All rights reserved.