Affiliation:
1. Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences University of British Columbia Kelowna British Columbia Canada
2. School of Human Science (Sport and Exercise Sciences) The University of Western Australia Perth Western Australia Australia
3. Children's Hospital of Eastern Ontario Research Institute Ottawa Ontario Canada
Abstract
AbstractThe purpose of this study was to examine the effect of an acute bout of prolonged sitting with and without exercise breaks on cerebrovascular function in 7‐ to 13‐year‐old children. Forty‐two children and adolescents were recruited to a crossover trial, with 15 girls (mean age 10.1 ± 2.5 years) and 16 boys (mean age 10.5 ± 1.3 years) completing the two trial conditions: SIT, uninterrupted sitting for 3 h and CYCLE, 3 h of sitting interrupted hourly with a 10‐min moderate intensity exercise break. Cerebrovascular function was measured Pre and Post SIT and CYCLE from blood flow (), diameter, and shear rate of the internal carotid artery (ICA) at rest and in response to CO2. Blood velocity in the middle (MCA) and posterior (PCA) cerebral arteries was assessed at rest, during a neurovascular coupling task (NVC) and in response to CO2. We demonstrate that SIT but not CYCLE reduced ICA cerebrovascular reactivity to CO2 (%Δ ICA /Δ end‐tidal CO2: SIT: Pre 5.0 ± 2.4%/mmHg to Post 3.3 ± 2.8%/mmHg vs. CYCLE: Pre 4.4 ± 2.3%/mmHg to Post 5.3 ± 3.4%/mmHg, P = 0.05) and slowed the MCA blood velocity onset response time to hypercapnia (SIT: Pre 57.2 ± 32.6 s to Post 76.6 ± 55.2 s, vs. CYCLE: Pre 64.1 ± 40.4 s to Post 52.3 ± 28.8 s, P = 0.05). There were no changes in NVC. Importantly, breaking up prolonged sitting with hourly exercise breaks prevented the reductions in cerebrovascular reactivity to CO2 and the slowed intracranial blood velocity onset response time to hypercapnia apparent with uninterrupted sitting in children.
Subject
Physiology,Physiology (medical),Nutrition and Dietetics,Physiology,Physiology (medical),Nutrition and Dietetics