Variability of flow-mediated dilation measurements with repetitive reactive hyperemia

To capture the response of an acute intervention, multiple post intervention measurements of flow-mediated dilation (FMD) must be performed. The effect of repetitive reactive hyperemia on endothelial function and the measurement of FMD are unknown. The purpose of this investigation was (1) to examine the effect of repetitive reactive hyperemia on brachial artery FMD and (2) to determine whether brachial artery FMD is stable during a 2-h morning period. We investigated FMD in 20 apparently healthy college students on three randomized treatment days every 30 min (T30), 60 min (T60), and 120 min (T120) throughout a 2-h morning period (08.00 h to 10.00 h). An ANOVA (p > 0.05) and ICC (> 0.40) were both needed to confirm no difference among repetitive reactive hyperemia treatments. In response to repetitive reactive hyperemia, there was no difference (p = 0.307; ICC > 0.40) within the first and last FMD measurements of each treatment condition or between treatment conditions (p = 0.344; ICC > 0.40). FMD was similar (p = 0.348) throughout the 2-h morning period. In conclusion, repetitive reactive hyperemia over a 2-h period has no effect on FMD measurements in apparently healthy college students. In addition, this study found no time trends for FMD measurements during the 2-h morning period to allow for pre/post intervention FMD measurements.