title: Characterization of the brachial artery shear stress following walking exercise.
abstract: Habitual exercise provides repeated episodes of elevated vascular shear stress (SS), which may be a mechanism for repair of endothelial dysfunction in disease. Our aim was to determine the brachial artery SS during the 3-hour period following single bouts of low, moderate, and high-intensity walking exercise. In a randomized crossover design, 14 men walked for 45 minutes on a treadmill at 25%, 50% and 75% of VO2peak separated by 2-7 days. Using Doppler ultrasonography, brachial artery SS was assessed immediately after exercise and then hourly for 3 hours. High-intensity walking elicited greater (p<0.05) post-exercise SS compared with low and moderate intensity. In addition, a 3x4 (intensity x time) ANOVA indicated an absence of interaction (p=0.369) and a decline in post-exercise SS over time (p<0.0001) which was abolished after 2 hours. Thus, we found that brachial artery SS is greatest following high-intensity walking and that the rate of decline in SS is similar across all walking intensities.
authors.affiliation: Clinical Exercise Physiology Laboratory, Department of Kinesiology, Indiana University, Bloomington, IN 47405, USA. jpadilla@indiana.edu
authors.forename: Jaume
authors.initials: J
authors.lastname: Padilla
authors.forename: Ryan A
authors.initials: RA
authors.lastname: Harris
authors.forename: Lawrence D
authors.initials: LD
authors.lastname: Rink
authors.forename: Janet P
authors.initials: JP
authors.lastname: Wallace
mesh_terms: D000368:Aged; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D018592:Cross-Over Studies; D004730:Endothelium, Vascular / Q000502:physiology; D005080:Exercise Test; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D011897:Random Allocation; D013314:Stress, Mechanical; D013997:Time Factors; D018608:Ultrasonography, Doppler; D016138:Walking