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首页> 外文期刊>American Journal of Physiology >Acute ascorbic acid ingestion increases skeletal muscle blood flow and oxygen consumption via local vasodilation during graded handgrip exercise in older adults
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Acute ascorbic acid ingestion increases skeletal muscle blood flow and oxygen consumption via local vasodilation during graded handgrip exercise in older adults

机译：急性抗坏血酸摄入通过局部血管在老年人的分级手柄运动中增加骨骼肌血流和氧气消耗

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摘要

Human aging is associated with reduced skeletal muscle perfusion during exercise, which may be a result of impaired endothelium-dependent dilation and/or attenuated ability to blunt sympathetically mediated vasoconstriction. Intra-arterial infusion of ascorbic acid (AA) increases nitric oxide-mediated vasodilation and forearm blood flow (FBF) during handgrip exercise in older adults, yet it remains unknown whether an acute oral dose can similarly improve FBF or enhance the ability to blunt sympathetic vasoconstriction during exercise. We hypothesized that 1) acute oral AA would improve FBF (Doppler ultrasound) and oxygen consumption (V_(O_2)) via local vasodilation during graded rhythmic handgrip exercise in older adults (protocol 1), and 2) AA ingestion would not enhance sympatholysis in older adults during handgrip exercise (protocol 2). In protocol 1 (n = 8; 65 ± 3 yr), AA did not influence FBF or V_(O_2) during rest or 5% maximal voluntary contraction (MVC) exercise, but increased FBF (199 ± 13 vs. 248 ± 16 ml/min and 343 ± 24 vs. 403 ± 33 ml/min; P < 0.05) and V_(O_2) (26 ± 2 vs. 34 ± 3 ml/min and 43 ± 4 vs. 50 ± 5 ml/min; P < 0.05) at both 15 and 25% MVC, respectively. The increased FBF was due to elevations in forearm vascular conductance (FVC). In protocol 2 (n = 10; 63 ± 2 yr), following AA, FBF was similarly elevated during 15% MVC (~20%); however, vasoconstriction to reflex increases in sympathetic activity during -40 mmHg lower-body negative pressure at rest (ΔFVC: -16 ± 3 vs. -16 ± 2%) or during 15% MVC (ΔFVC: -12 ± 2 vs. -11 ± 4%) was unchanged. Our collective results indicate that acute oral ingestion of AA improves muscle blood flow and V02 during exercise in older adults via local vasodilation.
机译：人类衰老与运动过程中的骨骼肌灌注减少有关，这可能是依赖于内皮依赖性扩张和/或减毒的钝化介导的血管收缩的损伤能力的结果。抗坏血酸（AA）的动脉内输注增加了老年人手柄锻炼期间的一氧化氮介导的血流和前臂血流（FBF），但急性口服剂量是否可以同样改善FBF或增强钝性的能力，但它仍然未知。运动过程中的血管收缩。我们假设1）急性口腔AA将通过局部血管舒张在老年人的分级节奏手柄运动期间改善FBF（多普勒超声）和氧气消耗（V_（O_2））（协议1），2）AA摄入不会增强同情手柄运动期间的老年人（协议2）。在方案1（n = 8; 65±3 YR）中，AA在休息期间不影响FBF或V_（O_2）或5％最大自愿收缩（MVC）运动，但FBF（199±13 vs.248±16毫升）增加/ min和343±24与403±33ml / min; p <0.05）和V_（O_2）（26±2 vs.34±3ml / min，43±4与50±5 ml / min; p <0.05）分别在15％和25％MVC。增加的FBF是由于前臂血管传导（FVC）的升高。在方案2（n = 10; 63±2 YR）中，在AA之后，在15％MVC（〜20％）期间，FBF类似地升高;然而，血管收缩到反射在-40mmHg下体负压下的交感神经活动（Δfvc：-16±3与-16±2％）或15％MVC（ΔFVC：-12±2 Vs. - 11±4％）不变。我们的集体结果表明，通过局部血管舒张，急性口服摄入AA在老年人的运动期间改善了肌肉血液流动和V02。

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