Premium
Thirty minutes of handgrip exercise potentiates flow‐mediated dilatation in response to sustained and transient shear stress stimuli to a similar extent
Author(s) -
McPhee I. A. C.,
Pyke K. E.
Publication year - 2018
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/ep087065
Subject(s) - transient (computer programming) , shear stress , medicine , cardiology , mechanics , physics , computer science , operating system
New FindingsWhat is the central question of this study? This study sought to determine whether enhancement of brachial artery flow‐mediated dilatation (FMD) after acute exposure to a sustained elevation in shear stress is greater when the shear stress stimulus for FMD is also sustained.What is the main finding and its importance? Brachial artery FMD in response to a sustained (handgrip exercise) and transient (reactive hyperaemia) shear stress stimulus was enhanced to a similar extent 10 min after a 30 min handgrip exercise intervention. This suggests that prior exposure to a sustained elevation in shear stress results in a similar acute augmentation of the ability of the endothelium to transduce sustained and transient shear stress stimuli.Abstract Brief (30 min) exposure of the brachial artery (BA) to a sustained elevation in shear stress has been shown to potentiate subsequent BA flow‐mediated dilatation (FMD) in response to a transient shear stress stimulus [reactive hyperaemia (RH) FMD]. It is unknown whether matching the sustained shear stress exposure to a subsequent sustained shear stress stimulus for FMD [via handgrip exercise (SS‐FMD)] might enhance the potentiation of FMD. The purpose of the study, therefore, was to assess the impact of a 30 min handgrip exercise intervention‐induced elevation in shear stress on subsequent BA SS‐FMD versus RH‐FMD. Nineteen healthy men (22 ± 3 years) preformed a 30 min rhythmic handgrip exercise intervention on two experimental days. BA‐FMD was assessed using either an RH or a 6 min sustained shear stress stimulus created via handgrip exercise (order of visits counterbalanced) at three time points: pre‐intervention and 10 and 60 min post‐intervention. The FMD was assessed using duplex ultrasound. Shear stress was estimated as shear rate (SR = BA blood velocity/BA diameter). Data are mean ± SD. Both SS and RH‐FMD increased from pre‐intervention to 10 min post‐intervention [SS‐FMD (6 min average), from 0.11 ± 0.05 to 0.16 ± 0.08 mm; P = 0.008; Cohen's d = 0.66; and RH‐FMD, from 0.25 ± 0.1 to 0.32 ± 0.11 mm; P = 0.013; Cohen's d = 0.68]. The magnitude of enhancement in RH and SS‐FMD did not differ (change in RH versus SS‐FMD pre‐ versus 10 min post‐intervention, P = 0.344). These findings suggest that exposure to elevated shear stress via 30 min of handgrip exercise potentiates subsequent FMD in response to sustained and transient elevations in shear stress to a similar extent.