Lower-limb arteries, such as the popliteal artery, are a common site of atherosclerosis. Furthermore, they are habitually exposed to large fluctuations in blood flow during physical and sedentary activities. Low-flow-mediated constriction (L-FMC) and flow-mediated dilation (FMD) provide indices of endothelial-dependent vasoconstriction and vasodilation, respectively. Age and sex both impact upper-limb FMD. However, it is unclear whether these factors also influence popliteal endothelial-dependent function. Popliteal endothelial function was compared between younger and older males and females (n=14 per group) matched for age- and sex-specific relative aerobic fitness levels (each group's normative percentile: ~45%). Nitroglycerin-mediated dilation (NMD) was also assessed as a measure of endothelial-independent vasodilation. Ageing reduced relative popliteal FMD in both males (older: 4.3±1.8% versus younger 5.7±1.9%) and females (older: 2.9±1.8% versus younger: 6.1±1.6%, both: P<0.046). FMD was also lower in older females versus older males (P=0.04). Popliteal NMD findings followed the same pattern as FMD. Compared to younger adults, relative L-FMC responses were blunted among older males (older: −1.2±1.1% versus younger: −2.2±1.0%) and females (older: −1.0±1.2% versus younger: −2.1±1.3%, both P<0.03) with no sex-differences observed in either age group (all, P>0.60). The adverse age- and sex-related (older adults only) declines in popliteal FMD were mediated, in part, by reduced vascular smooth muscle sensitivity to nitric oxide. Endothelial-dependent vasoconstriction was also attenuated with age, but unaffected by sex. Despite similar normative aerobic fitness percentiles (~45%), older adults exhibited attenuated popliteal endothelial function than their younger counterparts. This was particularly evident in older females who exhibited the lowest endothelial-dependent vasodilatory responses.

下肢动脉，例如the动脉，是动脉粥样硬化的常见部位。此外，他们习惯性地在身体和久坐活动期间暴露于血流的大波动中。低流量介导的收缩（L-FMC）和流量介导的扩张（FMD）分别提供了内皮依赖性血管收缩和血管舒张的指标。年龄和性别都会影响上肢FMD。然而，目前尚不清楚这些因素是否也影响pop内皮依赖性功能。比较青年和老年男性和女性的endo内皮功能（n每组= 14）与特定年龄和性别的相对有氧适应水平相匹配（每组的标准百分位数：〜45％）。硝酸甘油介导的扩张（NMD）也被评估为内皮依赖性血管扩张的指标。衰老男性和女性（年龄较大：4.3±1.8％相对年轻的5.7±1.9％）和女性（年龄较大：2.9±1.8％相对年轻的6.1±1.6％，两者均降低相对P骨FMD，两者均：P <0.046）。女性的口蹄疫也低于男性（P = 0.04）。N NMD的发现与FMD遵循相同的模式。与年轻人相比，男性（老年人：-1.2±1.1％，年轻人：-2.2±1.0％）和女性（老年人：-1.0±1.2％相对于年轻人：-2.1±1.3％）的相对L-FMC反应减弱，都P<0.03），两个年龄段均未观察到性别差异（所有，P > 0.60）。pop骨FMD的与年龄和性别相关的不利下降（仅针对成年人）部分是由血管平滑肌对一氧化氮敏感性降低所引起的。内皮依赖性血管收缩也随着年龄而减弱，但不受性别影响。尽管有氧健身规范百分位数相似（〜45％），但老年人的than内皮功能减弱。这在表现出最低的内皮依赖性血管舒张反应的老年女性中尤为明显。