Murrell Carissa J, Cotter James D, Thomas Kate N, Lucas Samuel J E, Williams Michael J A, Ainslie Philip N
Department of Physiology, University of Otago, Dunedin, New Zealand.
Age (Dordr). 2013 Jun;35(3):905-20. doi: 10.1007/s11357-012-9414-x. Epub 2012 Jun 6.
Chronic reductions in cerebral blood flow (CBF) and cerebrovascular reactivity to CO2 are risk factors for cerebrovascular disease. Higher aerobic fitness is associated with higher CBF at any age; however, whether CBF or reactivity can be elevated following an exercise training intervention in healthy individuals is unknown. The aim of this study was to assess the effect of exercise training on CBF and cerebrovascular reactivity at rest and during exercise in young and older individuals. Ten young (23 ± 5 years; body mass index (BMI), 26 ± 3 kg m(-2); [Formula: see text], 35 ± 5 ml kg(-1) min(-1)) and 10 older (63 ± 5 years; BMI, 25 ± 3.0 kg m(-2); [Formula: see text], 26 ± 4 ml kg(-1) min(-1)) previously sedentary individuals breathed 5 % CO2 for 3 min at rest and during steady-state cycling exercise (30 and 70 % heart rate range (HRR)) prior to and following a 12-week aerobic exercise intervention. Effects of training on middle cerebral artery blood velocity (MCAv) at rest were unclear in both age groups. The absolute MCAv response to exercise was greater in the young (9 and 9 cm s(-1) (30 and 70 % HRR, respectively) vs. 5 and 4 cm s(-1) (older), P < 0.05) and was similar following training. Cerebrovascular reactivity was elevated following the 12-week training at rest (2.87 ± 0.76 vs. 2.54 ± 1.12 cm s(-1) mm Hg(-1), P = 0.01) and during exercise, irrespective of age. The finding of a training-induced elevation in cerebrovascular reactivity provides further support for exercise as a preventative tool in cerebrovascular and neurological disease with ageing.
慢性脑血流量（CBF）减少以及脑血管对二氧化碳的反应性降低是脑血管疾病的危险因素。在任何年龄，较高的有氧适能都与较高的脑血流量相关；然而，健康个体在进行运动训练干预后，脑血流量或反应性是否能提高尚不清楚。本研究的目的是评估运动训练对年轻人和老年人静息及运动时脑血流量和脑血管反应性的影响。10名年轻受试者（23±5岁；体重指数（BMI），26±3 kg/m²；[公式：见正文]，35±5 ml·kg⁻¹·min⁻¹）和10名老年受试者（63±5岁；BMI，25±3.0 kg/m²；[公式：见正文]，26±4 ml·kg⁻¹·min⁻¹），此前均久坐不动，在进行为期12周的有氧运动干预之前和之后，于静息状态以及稳态骑行运动（心率范围（HRR）的30%和70%）期间呼吸5%二氧化碳达3分钟。在两个年龄组中，训练对静息时大脑中动脉血流速度（MCAv）的影响均不明确。年轻人运动时MCAv的绝对反应更大（分别为9和9 cm/s（30%和70% HRR），而老年人为5和4 cm/s，P<0.05），训练后情况相似。经过12周训练后，无论年龄大小，静息时（2.87±0.76 vs. 2.54±1.12 cm·s⁻¹·mmHg⁻¹，P = 0.01）和运动时脑血管反应性均有所提高。训练引起的脑血管反应性升高这一发现为运动作为预防衰老相关脑血管和神经疾病的工具提供了进一步支持。
