Date of Award

Spring 5-11-2018

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Kinesiology

Committee Chair

Dr. Daniel Credeur

Committee Chair Department

Kinesiology

Committee Member 2

Dr. Scott Piland

Committee Member 2 Department

Kinesiology

Committee Member 3

Dr. Trenton Gould

Committee Member 3 Department

Kinesiology

Abstract

Prolonged sitting (3-6 hours) negatively impacts peripheral vascular health. Whether sitting similarly impacts central cardiovascular hemodynamics and vascular stiffness is unknown. Purpose: Determine if prolonged sitting increases central blood pressure, aortic pulse wave reflection and vascular stiffness. Methods: In 10 subjects (Age=22±2 yrs, BMI=28±4kg/m2, 3 females), brachial artery pulse wave analysis was performed before (baseline-BL), during, and after 3 hours of sitting. Aortic pulse wave velocity (PWV) was examined before and after sitting using carotid applanation tonometry coupled with oscillometry performed on left upper-thigh. For mechanistic insight, intermittent pneumatic compression (IPC) was applied during sitting (i.e., 3, 120 mmHg compression cycles per minute, 30 mins on/off) in a sub-set (N=9). Results: During sitting, there was no change in heart rate (P>0.05); however, it tended (p=0.079) to be lower with IPC. No changes were noted for central blood pressure during sitting, with or without IPC (p>0.05). Augmentation pressure and index (AIx), wave reflection height and magnitude all exhibited significant decreases over course of sitting, most notable at 180 mins (e.g., AIx at BL=7±5, vs. 180 mins sitting=-3±3%, p=0.03). IPC appeared to mitigate these changes (sitting with vs. without IPC; AIx, 120 mins diff in mean=9.7%, p=0.018). No change was observed for aortic PWV in response to sitting, with or without IPC (p>0.05). Conclusion: Prolonged sitting decreases aortic pulse wave reflection but does not impact vascular stiffness. IPC tends to reduce heart rate and restrain central hemodynamic changes which may be the result of a reduction in venous pooling in the legs.

ORCID ID

orcid.org/0000-0001-8906-4657

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