The influence of sex and maturation on carotid and vertebral artery hemodynamics and associations with free-living (in)activity in 6-17 year-olds.

We explored the influence of sex and maturation on resting cervical artery hemodynamics (common carotid artery, CCA; internal carotid artery, ICA; and vertebral artery, VA) and free-living physical activity and sedentary behavior in children 6-17 years of age. Additionally, we investigated the relationship between physical activity and sedentary behavior and cervical artery hemodynamics. Seventy-eight children and adolescents, girls (n=42; mean age 11.4 ± 2.5 years) and boys (n=36; mean age 11.0 ± 2.6 years), completed anthropometric measures, duplex ultrasound assessment of the cervical arteries, and wore an activPAL accelerometer to assess physical activity (indexed by steps/day) and sedentary behavior for seven days. The ICA and VA diameter was similar between pre-pubertal and pubertal groups, as was volumetric blood flow (Q), however, the CCA diameter was significantly larger in the pubertal group (P < .05). Boys were found to have larger diameters in all cervical arteries than girls, as well as higher QCCA, QICA and global cerebral blood flow (P < .05). The pubertal group was more sedentary (100 min/day more; P < .05) and took 3500 fewer steps/day than the pre-pubertal group (P < .05). Shear rate (SR) and Q of the cervical arteries showed no relationship to physical activity or prolonged bouts of sedentary behavior; however, a significant negative relationship was apparent between total sedentary time and ICASR after covarying for steps/day and maturation (P < .05). These findings provide novel insight into the potential influence sedentary behavior may have on cerebrovascular blood flow in healthy girls and boys.