Division of Kinesiology, School of Health and Human Performance, Faculty of Health, Dalhousie University, Halifax, Nova Scotia, Canada.
J Appl Physiol (1985). 2019 Sep 1;127(3):679-687. doi: 10.1152/japplphysiol.00887.2018. Epub 2019 Jul 18.
An acute bout of prolonged sitting (PS) impairs the popliteal artery flow-mediated dilation (FMD) response. Despite equivocal reductions in mean shear rate, young women demonstrate an attenuated decline in popliteal FMD versus young men. However, it is uncertain whether popliteal endothelial-dependent vasoconstrictor responses [low-flow-mediated constriction (L-FMC)] are similarly affected by PS and/or whether sex differences exist. We tested the hypothesis that women would have attenuated reductions in both popliteal FMD and L-FMC responses following an acute bout of PS. Popliteal FMD and L-FMC responses were assessed via duplex ultrasonography before and after a 3-h bout of PS. These responses were then compared between 10 men (24 ± 2 yr) and 10 women (23 ± 2 yr) with similar ( > 0.13) levels of objectively measured habitual physical activity (via PiezoRx) and sedentary time (via activPAL). At baseline, men and women exhibited similar ( > 0.46) popliteal FMD (4.8 ± 1.2 vs. 4.5 ± 0.6%) and L-FMC (-1.7 ± 1.0 vs. -1.9 ± 0.9%) responses. Both sexes experienced identical (group: > 0.76; time: < 0.001) PS-induced impairments in popliteal FMD (-2.8 ± 1.4 vs. -2.6 ± 0.9%) and L-FMC (1.3 ± 0.7% vs. 1.4 ± 0.7%). In young adults, sex did not influence the negative PS-induced FMD, L-FMC, or microvascular responses in the lower limb. As such, our findings suggest that young men and women are similarly susceptible to the acute negative vascular effects of PS. Future studies should extend these findings to older, less physically active adults and/or patients with vascular disease. We compared changes in popliteal artery endothelial function to a single 3-h bout of sitting between young men and women. Both groups exhibited similar endothelial-dependent vasodilation (i.e., flow-mediated dilation) and endothelial-dependent vasoconstrictor responses (i.e., low-flow-mediated constriction) at baseline and equivocal impairments in these measures of endothelial function following prolonged sitting. These findings demonstrate that acute impairments in conduit artery endothelial health associated with uninterrupted sitting are not influenced by sex in young, healthy adults.
急性长时间坐姿（PS）会损害腘动脉血流介导的扩张（FMD）反应。尽管平均切变率降低，但年轻女性的腘动脉 FMD 下降幅度较年轻男性小。然而，目前尚不清楚 PS 是否会同样影响腘动脉内皮依赖性血管收缩反应[低流量介导的收缩（L-FMC）]，以及是否存在性别差异。我们假设女性在急性 PS 后，腘动脉 FMD 和 L-FMC 反应的降低幅度会减弱。通过双功能超声评估 PS 3 小时前后的腘动脉 FMD 和 L-FMC 反应。然后，将 10 名男性（24±2 岁）和 10 名女性（23±2 岁）的这些反应进行比较，这些人具有相似的（>0.13）客观测量的习惯性体力活动（通过 PiezoRx）和久坐时间（通过 activPAL）。在基线时，男性和女性的腘动脉 FMD（4.8±1.2%对 4.5±0.6%）和 L-FMC（-1.7±1.0%对-1.9±0.9%）反应相似（>0.46）。两种性别都经历了相同的（组：>0.76；时间：<0.001）PS 引起的腘动脉 FMD 损伤（-2.8±1.4%对-2.6±0.9%）和 L-FMC（1.3±0.7%对 1.4±0.7%）。在年轻成年人中，性别并未影响下肢的急性 PS 诱导的 FMD、L-FMC 或微血管反应。因此，我们的研究结果表明，年轻男性和女性同样容易受到 PS 急性负面血管效应的影响。未来的研究应将这些发现扩展到年龄较大、体力活动较少的成年人和/或患有血管疾病的患者。我们比较了年轻男性和女性单次 3 小时坐姿对腘动脉内皮功能的影响。两组在基线时均表现出相似的内皮依赖性血管扩张（即血流介导的扩张）和内皮依赖性血管收缩反应（即低流量介导的收缩），而在长时间坐姿后，这些内皮功能指标均出现了类似的损伤。这些发现表明，在年轻健康成年人中，与不间断坐姿相关的主要动脉内皮健康的急性损伤不受性别影响。
