Impacts of prolonged sitting with mild hypercapnia on vascular and autonomic function in healthy recreationally active adults.

Prolonged sitting, which is known to impair peripheral vascular function often occurs in spaces (e.g. offices) with mild hypercapnic atmospheres. However, the effects of prolonged sitting in hypercapnic conditions on vascular function are unknown. Therefore, the purpose of this study was to investigate the effects of prolonged sitting in mild hypercapnic conditions on vascular and autonomic function in humans. METHODS 12 healthy young adults participated in two experimental visits which consisted of sitting for 2.5 hours in a control condition (PSIT) or a mild hypercapnic condition (HCAP, CO2=1,500 ppm). During each visit, heart rate variability (HRV), blood pressure (BP), pulse wave velocity (PWV), augmentation index (AIx), brachial and popliteal artery flow mediated dilation (FMD), and near infrared spectroscopy (NIRS) were assessed before and after prolonged sitting. RESULTS Sitting significantly decreased AIx in both groups (P 0.05). CONCLUSION Prolonged sitting attenuated both brachial and popliteal endothelial function and was associated with perturbed microcirculation. Additionally, mild hypercapnic conditions further impaired peripheral endothelial and microvascular function. Together, these findings suggest that prolonged sitting is accompanied by a host of deleterious effects on the vasculature, which are exacerbated by mild hypercapnia.