Integrative Human Physiology Laboratory, Manning College of Nursing and Health Sciences, University of Massachusetts Boston, Boston, Massachusetts, United States.
Integrative Physiology Laboratory, College of Applied Health Sciences, University of Illinois at Chicago, Chicago, Illinois, United States.
Am J Physiol Heart Circ Physiol. 2023 Oct 1;325(4):H909-H916. doi: 10.1152/ajpheart.00349.2023. Epub 2023 Aug 18.
Sex differences in resting cerebral hemodynamics decline with aging. Given that acute resistance exercise (RE) is a hypertensive challenge, it may reveal sex-dependent abnormalities in cerebral hemodynamics. Thus, we hypothesized that cerebral blood velocity and pulsatility responses to RE would be sex-dependent in older adults. Fourteen older females and 11 males (50-68 yr) completed a high-intensity unilateral isokinetic knee flexion/extension exercise. Measurements were collected at baseline, immediately, 5- and 30-min post-RE. Blood pressure was measured via finger photoplethysmography. Mean middle cerebral artery blood velocity (MCAv) and pulsatility were assessed via transcranial Doppler ultrasound. Carotid pulsatility was obtained via duplex ultrasound. MCAv increased immediately after RE in older females [mean difference () = 6.02, 95% CI: 1.66 to 10.39 cm/s, < 0.001] but not in males ( = -0.72, 95% CI: -3.83 to 5.27 cm/s, = 0.99), followed by similar reductions 5-min post-RE in older females ( = -4.40, 95% CI: -8.81 to -0.10 cm/s, = 0.045) and males ( = -6.41, 95% CI: -11.19 to -1.62 cm/s, = 0.003). MCAv pulsatility increased similarly in older females ( = 0.24, 95% CI: 0.11 to 0.40, < 0.001) and males ( = 0.38, 95% CI: 0.20 to 0.53, < 0.001), persisting 5-min post-RE. Older females showed smaller increases in carotid pulsatility immediately after RE ( = 0.18, 95% CI: 0.03 to 0.38, = 0.01) than males ( = 0.48, 95% CI: 0.26 to 0.68, < 0.001). An exercise-mediated hypertensive stimulus revealed differential sex responses in MCAv and carotid pulsatility but not in cerebral pulsatility. Cerebral pulsatility findings suggest a similar sex susceptibility to cerebrovascular abnormalities following exercise-mediated hypertensive stimulus in older adults. Sex differences in resting cerebral hemodynamics decline with advancing age as females experience larger reductions in cerebral blood velocity and steeper pulsatility increases than males. However, an exercise-mediated hypertensive stimulus might reveal sex differences in cerebral hemodynamics not apparent at rest. Following high-intensity resistance exercise, older females but not males exhibit increases in cerebral blood velocity, despite similar increases in cerebral pulsatility. The susceptibility to cerebrovascular abnormalities following exercise-mediated hypertensive stimulus appears similar between sexes.
性别对大脑静息状态下血流动力学的影响会随着年龄的增长而下降。由于急性抗阻运动（RE）是一种高血压挑战，它可能会揭示大脑血流动力学的性别依赖性异常。因此，我们假设在老年人中，大脑血流速度和搏动性对 RE 的反应存在性别依赖性。14 名老年女性和 11 名男性（50-68 岁）完成了单侧高强度等动膝关节屈伸运动。在基线、运动后即刻、5 分钟和 30 分钟时进行测量。血压通过手指光体积描记法测量。通过经颅多普勒超声评估大脑中动脉平均血流速度（MCAv）和搏动性。通过双功能超声评估颈动脉搏动性。运动后即刻，老年女性的 MCAv 增加[平均差异（）= 6.02，95%置信区间：1.66 至 10.39cm/s，<0.001]，但男性没有（= -0.72，95%置信区间：-3.83 至 5.27cm/s，= 0.99），随后在老年女性（= -4.40，95%置信区间：-8.81 至 -0.10cm/s，= 0.045）和男性（= -6.41，95%置信区间：-11.19 至 -1.62cm/s，<0.001）中均出现类似的 5 分钟时降低。MCAv 搏动性在老年女性（= 0.24，95%置信区间：0.11 至 0.40，<0.001）和男性（= 0.38，95%置信区间：0.20 至 0.53，<0.001）中均以相似的方式增加，在 5 分钟时持续增加。与男性相比，老年女性运动后即刻颈动脉搏动性增加幅度较小（= 0.18，95%置信区间：0.03 至 0.38，= 0.01）。急性抗阻运动产生的高血压刺激反应显示出 MCAv 和颈动脉搏动性的性别差异，但大脑搏动性没有差异。大脑搏动性发现表明，在老年人中，运动介导的高血压刺激后，女性和男性可能对脑血管异常具有相似的易感性。与男性相比，女性在休息时大脑血流速度的降低和搏动性的增加幅度更大，导致性别对大脑静息状态下血流动力学的影响随年龄增长而下降。然而，运动介导的高血压刺激可能会揭示在休息时不明显的大脑血流动力学性别差异。在进行高强度抗阻运动后，尽管大脑搏动性增加幅度相似，但只有老年女性而非男性的大脑血流速度增加。运动介导的高血压刺激后对脑血管异常的敏感性在两性之间似乎相似。
