Jones Raymond, McArthur Dominique, McCoy Stephanie M, Stoner Lee, Fryer Simon, Credeur Daniel P
Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
School of Kinesiology and Nutrition, University of Southern Mississippi, Hattiesburg, MS, USA.
Int J Exerc Sci. 2022 Aug 1;15(2):1156-1167. doi: 10.70252/BZQJ6904. eCollection 2022.
Reductions in brain blood flow are associated with reduced cognitive function and cerebrovascular disease. Acute periods of uninterrupted sitting can lead to endothelial dysfunction, namely due to a reduction in shear stress and subsequent reduction in nitric oxide bioavailability. Little is known of the impact of sitting on brain health. The purpose o determine the total brain blood flow response following a 60-minute bout of uninterrupted sitting. Using a parallel design, this study evaluated the impact of 60-minutes of sitting on total brain blood flow. Fifteen participants (n=15; age=24 ± 1yr; BMI=25 ± 1 kg/m) sat, uninterrupted, for 60-minutes during the SIT protocol. To ascertain the contribution of blood pooling effects on total brain blood flow, ten participants (n=10; age=23±2yr; BMI=27±4 kg/m) sat in a modified sitting (MOD) for 60-minutes. Finally, thirteen participants (n=13; age=23±3yr; BMI=26±4 kg/m) remained supine for the duration of the 60-minutes as a time-control (TC). Brain blood flow was quantified through Doppler-ultrasound measurements of blood flow through the internal carotid (ICA) and vertebral (VA) arteries: (ICA blood flow + VA blood flow) × 2. Following the 60-minutes of sitting (SIT), there was a significant reduction in brain blood flow with time (=0.001, =0.05). Total brain blood flow did not significantly change in MOD (=0.69, =0.05) or TC (=0.06, =0.58) conditions. These findings indicate 60-minutes of sitting may alter cerebrovascular hemodynamics characterized by a reduction in total brain blood flow.
脑血流量减少与认知功能下降和脑血管疾病有关。长时间不间断坐着的急性期会导致内皮功能障碍，这主要是由于剪切应力降低以及随后一氧化氮生物利用度降低所致。目前对久坐对大脑健康的影响知之甚少。本研究的目的是确定60分钟不间断久坐后全脑血流的反应。采用平行设计，本研究评估了60分钟久坐对全脑血流的影响。15名参与者（n = 15；年龄 = 24±1岁；BMI = 25±1 kg/m²）在久坐方案中不间断地坐了60分钟。为了确定血液淤积效应对全脑血流的影响，10名参与者（n = 10；年龄 = 23±2岁；BMI = 27±4 kg/m²）以改良坐姿（MOD）坐了60分钟。最后，13名参与者（n = 13；年龄 = 23±3岁；BMI = 26±4 kg/m²）仰卧60分钟作为时间对照（TC）。通过多普勒超声测量颈内动脉（ICA）和椎动脉（VA）的血流来量化脑血流量：（ICA血流量 + VA血流量）×2。60分钟久坐（SIT）后，脑血流量随时间显著减少（P = 0.001，效应量 = 0.05）。在MOD组（P = 0.69，效应量 = 0.05）或TC组（P = 0.06，效应量 = 0.58）条件下，全脑血流量没有显著变化。这些发现表明，60分钟的久坐可能会改变以全脑血流量减少为特征的脑血管血流动力学。
