Griffith Sports Science, Griffith University, Gold Coast, QLD, 4222, Australia.
Sport Performance Innovation and Knowledge Excellence Unit, Queensland Academy of Sport, Nathan, QLD, 4111, Australia.
Eur J Appl Physiol. 2022 Aug;122(8):1949-1964. doi: 10.1007/s00421-022-04964-w. Epub 2022 Jun 8.
To compare physiological responses to submaximal cycling and sprint cycling performance in women using oral contraceptives (WomenOC) and naturally cycling women (WomenNC) and to determine whether N-acetylcysteine (NAC) supplementation mediates these responses.
Twenty recreationally trained women completed five exercise trials (i.e., an incremental cycling test, a familiarisation trial, a baseline performance trial and two double-blind crossover intervention trials). During the intervention trials participants supplemented with NAC or a placebo 1 h before exercise. Cardiopulmonary parameters and blood biochemistry were assessed during 40 min of fixed-intensity cycling at 105% of gas-exchange threshold and after 1-km cycling time-trial.
WomenOC had higher ventilation (β [95% CI] = 0.07 L·min [0.01, 0.14]), malondialdehydes (β = 12.00 mmol·L [6.82, 17.17]) and C-reactive protein (1.53 mg·L [0.76, 2.30]), whereas glutathione peroxidase was lower (β = 22.62 mU·mL [- 41.32, - 3.91]) compared to WomenNC during fixed-intensity cycling. Plasma thiols were higher at all timepoints after NAC ingestion compared to placebo, irrespective of group (all p < 0.001; d = 1.45 to 2.34). For WomenNC but not WomenOC, the exercise-induced increase in malondialdehyde observed in the placebo trial was blunted after NAC ingestion, with lower values at 40 min (p = 0.018; d = 0.73). NAC did not affect cycling time-trial performance.
Blood biomarkers relating to oxidative stress and inflammation are elevated in WomenOC during exercise. There may be an increased strain on the endogenous antioxidant system during exercise, since NAC supplementation in WomenOC did not dampen the exercise-induced increase in malondialdehyde. Future investigations should explore the impact of elevated oxidative stress on exercise adaptations or recovery from exercise in WomenOC.
比较使用口服避孕药（OC 组）和自然排卵女性（NC 组）的女性亚极量踏车运动和冲刺踏车运动的生理反应，并确定 N-乙酰半胱氨酸（NAC）补充是否会影响这些反应。
20 名有规律运动的女性完成了 5 项运动试验（即递增踏车试验、熟悉试验、基础运动能力试验和 2 项双盲交叉干预试验）。在干预试验中，参与者在运动前 1 小时补充 NAC 或安慰剂。在固定强度踏车运动（强度为换气阈的 105%）40 分钟和 1 公里计时赛结束后评估心肺参数和血液生化指标。
OC 组的通气量（β[95%置信区间] = 0.07 L·min[0.01，0.14]）、丙二醛（β = 12.00 mmol·L[6.82，17.17]）和 C 反应蛋白（1.53 mg·L[0.76，2.30]）更高，而谷胱甘肽过氧化物酶（β = -22.62 mU·mL[-41.32，-3.91]）更低，与 NC 组相比，在固定强度踏车运动时。与安慰剂相比，无论组别如何，NAC 摄入后所有时间点的血浆硫醇水平均升高（均 < 0.001；d = 1.45 至 2.34）。对于 NC 组，但不是 OC 组，在安慰剂试验中观察到的运动诱导的丙二醛增加在 NAC 摄入后减弱，在 40 分钟时值更低（p = 0.018；d = 0.73）。NAC 对计时赛运动能力没有影响。
在运动期间，OC 组与氧化应激和炎症相关的血液生物标志物升高。由于 NAC 补充并未抑制 OC 组运动诱导的丙二醛增加，因此运动期间内源性抗氧化系统可能受到更大的压力。未来的研究应探讨氧化应激升高对 OC 女性运动适应或运动后恢复的影响。
