Differences in Blood Flow Patterns and Endothelial Shear Stress at the Carotid Artery Using Different Exercise Modalities and Intensities

Abstract

Endothelial dysfunction is the first pathophysiological step of atherosclerosis, which is responsible for 90% of strokes. Exercise programs aim to reduce the risk of developing stroke; however, the majority of the beneficial factors of exercise are still unknown. Endothelial shear stress (ESS) is associated with endothelial homeostasis. Unfortunately, ESS has not been characterized during different exercise modalities and intensities in the carotid artery. Therefore, the purpose of this study was to determine exercise-induced blood flow patterns in the carotid artery. Fourteen apparently healthy young adults (males = 7, females = 7) were recruited for this repeated measures study design. Participants completed maximal oxygen consumption (VO2max) tests on a Treadmill, Cycle-ergometer, and Arm-ergometer, and 1-repetition maximum (1RM) tests of the Squat, Bench Press (Bench), and Biceps Curl (Biceps) on separate days. Thereafter, participants performed each exercise at 3 different exercise intensities (low, moderate, high) while a real-time ultrasound image and blood flow of the carotid artery was obtained. Blood flow patterns were assessed by estimating ESS via Womersley’s estimation and turbulence via Reynold’s number (Re). Data were analyzed using a linear mixed-effects model. Pairwise comparisons with Holm-Bonferroni correction were conducted with Hedge’s g effect size to determine the magnitude of the difference. There was a main effect of intensity, exercise modality, and intensity * exercise modality interaction on both ESS (p < 0.001). Treadmill at a high intensity yielded the greatest ESS when compared to the other exercise modalities and intensities, while Bench Press and Biceps curls yielded the least ESS. All exercise intensities across all modalities resulted in turbulent blood flow. Clinicians must take into consideration how different exercise modalities and intensities affect ESS and Re of the carotid artery.

Thrombin Generation Thresholds for Coagulation Initiation under Flow

“…First, we must validate the framework's utility by comparing its efficacy and safety to other assay methods in randomized clinical trials. In a forthcoming work, we will evaluate the effect of aerobic exercise on the risk of developing blood coagulation disorders using data collected from real subjects [46,47].…”

Water-soluble tomato concentrate modulates shear-induced platelet aggregation and blood flow in vitro and in vivo

“…If blood flow in a normal vessel increases, for example, due to exercise, the wall shear rate increases proportionally with the flow rate. A significant increase in shear stress was observed at high-intensity exercise in the carotid artery, from resting with 26.5 ± 3.3 dynes/cm 2 to high-intensity cycling with 77.5 ± 20.3 dynes/cm 2 (5). A high-flow shear stress can directly activate platelets and lead to aggregation (6).…”