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Association beween resting heart rate, shear and flow‐mediated dilation in healthy adults
Author(s) -
Fox Brandon M.,
Brantley Lucy,
White Claire,
Seigler Nichole,
Harris Ryan A.
Publication year - 2014
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/expphysiol.2014.080960
Subject(s) - shear rate , cardiology , medicine , resting heart rate , shear (geology) , shear stress , heart rate , brachial artery , heart failure , blood pressure , biology , physics , mechanics , viscosity , paleontology , quantum mechanics
New FindingsWhat is the central question of this study? The aim was to explore the relationships among resting heart rate, shear and endothelial function in humans.What is the main finding and its importance? The main finding is that resting heart rate is associated with shear and endothelial function in humans. This finding could have implications when studying endothelial function in humans with varying heart rates.Preclinical data have demonstrated that heart rate (HR) can directly impact vascular endothelial function, in part, through a shear‐stress mechanism. This study sought to explore, in humans, the associations between resting heart rate and both shear and endothelial function assessed by flow‐mediated dilation (FMD). The brachial artery FMD test was performed in 31 apparently healthy volunteers. Basal (B) and hyperaemic (H) shear were quantified in the following two ways using data from the FMD test: the traditional cumulative shear area under the curve up to peak dilation (Shear cum ) method; and our novel method of shear summation (Shear sum ), which accounts for HR by summing each individual cardiac cycle shear up to peak dilation. Data were grouped by tertiles based on resting HR as follows: low (LHR = 43–56 beats min −1 ; n = 10); middle (MHR = 58–68 beats min −1 ; n = 11); and high (HHR = 69–77 beats min −1 ; n = 10). Within the LHR group, both B‐Shear cum and H‐Shear cum were significantly higher ( P < 0.001) than B‐Shear sum and H‐Shear sum , respectively, whereas in the HHR group B‐Shear cum and H‐Shear cum were significantly lower ( P < 0.001) than B‐Shear sum and H‐Shear sum , respectively. The FMD in the LHR group (8.8 ± 0.8%) was significantly greater than that in both the MHR group (5.5 ± 0.8%; P = 0.009) and the HHR group (5.9 ± 0.8%; P = 0.024). These findings demonstrate the existence of a relationship between heart rate and both shear and endothelial function in humans. Moreover, these findings have implications for considering heart rate as an important physiological variable when quantifying shear and performing the FMD test.