School of Sport and Health Sciences, St. Luke's Campus, University of Exeter, Heavitree Road, Exeter EX1 2LU, UK.
Respir Physiol Neurobiol. 2011 Jan 31;175(1):121-9. doi: 10.1016/j.resp.2010.10.002. Epub 2010 Oct 16.
We investigated the influence of the antioxidant N-acetylcysteine (NAC) on plasma nitrite concentration ([NO₂⁻]), pulmonary oxygen uptake (V(O₂)) kinetics and exercise tolerance. Eight males completed 'step' moderate- and severe-intensity cycle exercise tests following infusion of either NAC (125 mg kg⁻¹ h⁻¹ for 15 min followed by 25 mg kg⁻¹ h⁻¹ until the termination of exercise) or Placebo (PLA; saline). Following the initial loading phase, NAC infusion elevated plasma free sulfhydryl groups compared to placebo (PLA: 4 ± 2 vs. NAC: 13 ± 3 μ M g⁻¹; P < 0.05) and this elevation was preserved throughout the protocol. The administration of NAC did not significantly influence plasma [NO₂⁻] or V(O₂) kinetics during either moderate- or severe-intensity exercise. Although NAC did not significantly alter severe-intensity exercise tolerance at the group mean level (PLA: 776 ± 181 vs. NAC: 878 ± 284 s; P > 0.05), there was appreciable inter-subject variability in the response: four subjects had small reductions in exercise tolerance with NAC compared to PLA (-4%, -8%, -11%, and -14%) while the other four showed substantial improvements (+24%, +24%, +40%, and +69%). The results suggest that exercise-induced redox perturbations may contribute to fatigue development in recreationally-active adults.
我们研究了抗氧化剂 N-乙酰半胱氨酸 (NAC) 对血浆亚硝酸盐浓度 ([NO₂⁻])、肺氧摄取 (V(O₂)) 动力学和运动耐力的影响。8 名男性在接受 NAC（125mg/kg·h⁻¹ 输注 15 分钟，然后 25mg/kg·h⁻¹ 输注至运动结束）或安慰剂（PLA；生理盐水）输注后完成了“台阶”中度和重度强度的自行车运动测试。在初始加载阶段后，NAC 输注与安慰剂相比，使血浆游离巯基基团升高（PLA：4±2 与 NAC：13±3 μM g⁻¹；P<0.05），并且在整个方案中保持升高。NAC 给药在中度或重度强度运动期间均未显著影响血浆 [NO₂⁻] 或 V(O₂)动力学。尽管 NAC 并未显著改变重度强度运动耐力的组平均值水平（PLA：776±181 与 NAC：878±284s；P>0.05），但在个体之间存在明显的可变性：与 PLA 相比，有 4 名受试者的运动耐力有小幅度降低（-4%、-8%、-11%和-14%），而其他 4 名受试者则有明显提高（+24%、+24%、+40%和+69%）。结果表明，运动引起的氧化还原波动可能导致休闲活跃成年人的疲劳发展。
