The Impact of Sympathetic Nervous System Activity on Longitudinal Movements in the Carotid Artery of Young Healthy People

Arterial stiffness is a historically well-studied and reliable measurement used to assess vascular health and disease. However, recent research has emerged suggesting that arterial longitudinal wall motion is another key predictor in assessing cardiovascular disease and its associated risk factors. Arterial longitudinal wall motion is the oscillatory movement of the arterial wall in the anterograde (with blood flow) and retrograde (against blood flow) directions. Given its newly discovered application, it is imperative to understand the factors which contribute to the motion and their respective implications. One way to assess such factors is through activation of the sympathetic nervous system (SNS), also known as the “fight or flight” reflex. The physiological responses are varied and often involve changes in blood vessel wall dynamics. In this study, we acutely manipulate SNS activity using a cold pressor and a post-exercise circulatory occlusion test and monitor various parameters like blood pressure and artery stiffness, which may influence the longitudinal motion. The goal of this study is to gain further insight into the determinants of arterial longitudinal wall motion and under what conditions its measurement might be compromised. In doing so, its potential use as a clinical tool in predicting vascular disease may be improved