Department of Physical Therapy, Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan.
School of Health Science, Sapporo Medical University, Sapporo, Japan.
Eur J Appl Physiol. 2021 Sep;121(9):2471-2485. doi: 10.1007/s00421-021-04721-5. Epub 2021 May 24.
Exercise-induced increases in shear rate (SR) across different exercise intensities may differentially affect hypercapnia-induced vasodilation of the internal carotid artery (ICA), a potential index of cerebrovascular function. We aimed to elucidate the effects of exercise intensity on ICA SR during exercise and post-exercise hypercapnia-induced vasodilation of the ICA in young men.
Twelve healthy men completed 30 min of cycling at moderate [MIE; 65 ± 5% of age-predicted maximal heart rate (HR)] and high (HIE; 85 ± 5% HR) intensities. Hypercapnia-induced vasodilation was induced by 3 min of hypercapnia (target end-tidal partial pressure of CO + 10 mmHg) and was assessed at pre-exercise, 5 min and 60 min after exercise. Doppler ultrasound was used to measure ICA diameter and blood velocity during exercise and hypercapnia tests.
SR was not altered during either exercise (interaction and main effects of time; both P > 0.05). ICA conductance decreased during HIE from resting values (5.1 ± 1.3 to 3.2 ± 1.0 mL·min·mmHg; P < 0.01) but not during MIE (5.0 ± 1.3 to 4.0 ± 0.8 mL·min·mmHg; P = 0.11). Consequently, hypercapnia-induced vasodilation declined immediately after HIE (6.9 ± 1.7% to 4.0 ± 1.4%; P < 0.01), but not after MIE (7.2 ± 2.1% to 7.3 ± 1.8%; P > 0.05). Sixty minutes after exercise, hypercapnia-induced vasodilation returned to baseline values in both trials (MIE 8.0 ± 3.1%; HIE 6.4 ± 2.9%; both P > 0.05).
The present study showed blunted hypercapnia-induced vasodilation of the ICA immediately after high-intensity exercise, but not a moderate-intensity exercise in young men. Given that the acute response is partly linked to the adaptive response in the peripheral endothelial function, the effects of aerobic training on cerebrovascular health may vary depending on exercise intensity.
不同运动强度下的剪切率（SR）增加可能会对颈内动脉（ICA）的高碳酸血症诱导性血管舒张产生不同的影响，而 ICA 的这种血管舒张是脑血管功能的一个潜在指标。本研究旨在阐明运动强度对年轻人运动过程中 ICA-SR 以及运动后高碳酸血症诱导的 ICA 血管舒张的影响。
12 名健康男性完成了 30 分钟的中强度（MIE；预测最大心率的 65%±5%）和高强度（HIE；预测最大心率的 85%±5%）自行车运动。通过 3 分钟的高碳酸血症（目标呼气末 CO2 分压+10mmHg）来诱导 ICA 的高碳酸血症诱导性血管舒张，并在运动前、运动后 5 分钟和 60 分钟进行评估。多普勒超声用于测量运动和高碳酸血症测试期间的 ICA 直径和血流速度。
运动过程中 SR 没有改变（时间的交互和主要效应；均 P＞0.05）。与休息值相比，HIE 期间 ICA 传导降低（5.1±1.3 至 3.2±1.0mL·min·mmHg；P＜0.01），而 MIE 期间没有降低（5.0±1.3 至 4.0±0.8mL·min·mmHg；P=0.11）。因此，HIE 后立即出现高碳酸血症诱导性血管舒张下降（6.9±1.7%至 4.0±1.4%；P＜0.01），而 MIE 后没有下降（7.2±2.1%至 7.3±1.8%；P＞0.05）。运动后 60 分钟，两种试验中高碳酸血症诱导性血管舒张均恢复至基线值（MIE 8.0±3.1%；HIE 6.4±2.9%；均 P＞0.05）。
本研究表明，在年轻人中，高强度运动后 ICA 的高碳酸血症诱导性血管舒张减弱，但中强度运动没有减弱。鉴于急性反应与外周内皮功能的适应性反应部分相关，有氧运动对脑血管健康的影响可能因运动强度而异。
