Department of Life Sciences, School of Sciences, European University Cyprus, 1516 Nicosia, Cyprus.
Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, 61122 Thessaloniki, Greece.
Nutrients. 2023 Apr 18;15(8):1951. doi: 10.3390/nu15081951.
In sports nutrition, nitric oxide (NO) precursors such as L-citrulline are widely used to enhance NO bioavailability, which is considered an ergogenic aid. Our study aimed to examine the effect of short-term L-citrulline supplementation on respiratory muscles' performance, fatigue, and oxygenation in older adults. Fourteen healthy older males took 6 g of L-citrulline or a placebo for seven days in a double-blind crossover design. Pulmonary function via spirometry (i.e., forced expired volume in 1 s (FEV), forced vital capacity (FVC), and their ratio)), fractional exhaled nitric oxide (NO), maximal inspiratory pressure (MIP), rate of perceived exertion, and sternocleidomastoid muscle oxygenation (i.e., oxyhemoglobin (Δ[OHb]) and de-oxyhemoglobin (Δ[HHb]), total hemoglobin concentration (Δ[tHb]), and tissue saturation index (TSI%)) were evaluated at baseline, after seven days of L-citrulline supplementation, and after incremental resistive breathing to task failure of the respiratory muscles. The exhaled NO value was only significantly increased after the supplementation (26% < 0.001) in the L-citrulline condition. Pulmonary function, MIP, rate of perceived exertion, and sternocleidomastoid muscle oxygenation were not affected by the L-citrulline supplementation. In the present study, although short-term L-citrulline supplementation increased exhaled NO, no ergogenic aids were found on the examined parameters at rest and after resistive breathing to task failure in older adults.
在运动营养中，一氧化氮（NO）前体如瓜氨酸被广泛用于提高 NO 的生物利用度，这被认为是一种增强运动能力的辅助手段。我们的研究旨在探讨短期瓜氨酸补充对老年人呼吸肌性能、疲劳和氧合的影响。14 名健康的老年男性在双盲交叉设计中，连续 7 天每天服用 6 克瓜氨酸或安慰剂。通过肺活量测定法评估肺功能（即 1 秒用力呼气量（FEV）、用力肺活量（FVC）及其比值）、呼气末一氧化氮分数（NO）、最大吸气压力（MIP）、感觉用力程度和胸锁乳突肌氧合（即氧合血红蛋白（Δ[OHb]）和去氧血红蛋白（Δ[HHb]）、总血红蛋白浓度（Δ[tHb]）和组织饱和度指数（TSI%）），在基线、7 天瓜氨酸补充后和呼吸肌递增阻力呼吸至任务失败时进行评估。只有在瓜氨酸条件下，呼气末 NO 值在补充后才显著增加（26% < 0.001）。肺功能、MIP、感觉用力程度和胸锁乳突肌氧合不受瓜氨酸补充的影响。在本研究中，尽管短期瓜氨酸补充增加了呼气末 NO，但在老年人休息时和抵抗呼吸至任务失败后，没有发现对检查参数有任何增强运动能力的辅助作用。
