Hourly sitting interruptions did not significantly alter cerebrovascular hemodynamics, and central arterial stiffness was not correlated with middle cerebral artery velocity (r=-0.019, p=0.802).
Do hourly sitting interruptions (standing, walking) alter the relationship between cerebrovascular hemodynamics and arterial stiffness compared to uninterrupted sitting in healthy adults?
Acute changes in central arterial stiffness during sitting interruptions do not appear to directly influence cerebrovascular hemodynamics in healthy adults.
Mean Difference: -0.045 (95% CI -0.079–-0.011)
p-value: p=0.10
Andrew M Koessler1, Alexander Pomeroy1, Jeb F Struder1, Kristen M Paternoster1, Christopher E Grice1, Taylor Shorter1, Craig Paterson1,2, Gaurav Dave1, Bethany B Gibbs3, Feng-Chang Lin1, Michelle L Meyer1, Maihan B Vu1, and Erik D Hanson, FACSM1 1 University of North Carolina at Chapel Hill, Chapel Hill, NC, USA 27599 2 University of Bristol, Bristol, UK, BS8 2PS 3 West Virginia University, Morgantown, WV, USA 260506 Prolonged sitting acutely increases central arterial stiffness and may impair cerebrovascular hemodynamics, yet direct systemic-cerebrovascular relationships remain unclear. Interrupting sitting may mitigate these effects, but whether changes in arterial stiffness directly translate to cerebrovascular responses is not established. PURPOSE: This study examined the relationships among middle cerebral artery velocity (MCAv), cerebrovascular conductance index (CVCi), carotid-femoral pulse wave velocity (cfPWV), and mean arterial pressure (MAP) across sitting interruption strategies, using partial correlation analyses to isolate associations independent of blood pressure. METHODS: 33 healthy adults (82% female, 46.6 ± 5.9 years, 88% white) completed 4 visits under different conditions: (1) 4h of uninterrupted sitting (control) and hourly (2) standing, (3) walking, and (4) combined standing/walking interruptions. After semi-recumbent rest, cfPWV was assessed and MAP was derived via pulse wave analysis. MCAv was measured using transcranial doppler ultrasound and CVCi was calculated by dividing MCAv by MAP. Measures were collected pre- and post- condition. Results were analyzed using partial correlations controlling for MAP where appropriate, with a secondary correlation between MCAv and MAP conducted based on prior evidence of an association. RESULTS: CVCi declined with prolonged sitting independent of condition (MD = -0.045, 95%CI -0.079 - -0.011, p = 0.10), though it did not reach statistical significance, whereas MCAv and cfPWV did not change across time or condition (p > 0.05). No significant correlations were found between cfPWV and MCAv (r = -0.019, p = .802) or CVCi (r = -0.019, p = .795), when controlling for MAP. Additionally, MCAv was not associated with MAP (r = 0.097, p = .192). CONCLUSIONS: Acute changes in central arterial stiffness may not directly influence cerebrovascular hemodynamics in healthy adults. Additionally, MCAv showed no association with MAP, which may reflect the limited statistical power inherent to a feasibility study. Ongoing analyses will investigate this relationship in a larger sample size with additional vascular assessments. FUNDING SOURCE: National Heart, Lung, and Blood Institute of the National Institutes of Health under Award Number R01HL157187.
Andrew Koessler (Tue,) conducted a other in Healthy adults (n=33). Sitting interruption strategies (standing, walking, combined) vs. 4h of uninterrupted sitting was evaluated on Cerebrovascular conductance index (CVCi) change (MD -0.045, 95% CI -0.079 to -0.011, p=0.10). Hourly sitting interruptions did not significantly alter cerebrovascular hemodynamics, and central arterial stiffness was not correlated with middle cerebral artery velocity (r=-0.019, p=0.802).