The reduction in shear stress during cuff-occlusion has been hypothesized to mediate reactivity to low-flow. However, shear stress-dose dependence of reactivity to low-flow in the brachial artery (BA) is unclear. Furthermore, reactivity to low-flow in BA seems to vary from vasoconstriction to vasodilation, which could affect a subsequent flow-mediated dilation (FMD) response. This study examined whether reactivity to low-flow would be dependent on the magnitude of shear rate (SR) reduction in individuals with diverse cardiovascular risk profiles, and whether reactivity to low-flow would influence FMD. Data from 165 individuals were analysed and divided into the increased cardiovascular risk group (CVR: n=115, 85M, 67.0±8.8yrs) and control group (CTRL: n=50, 30M, 63.2±7.2yrs). BA diameter and blood velocity data obtained from Doppler ultrasound were used for calculation of FMD, reactivity to low-flow and estimated SR using edge-detection software. There was no correlation between reactivity to low-flow and the magnitude of SR reduction. There was a significant correlation between FMD and reactivity to low-flow in overall (r=0.261), CTRL (r=0.365) and CVR (r=0.189, all p<0.05) groups. Multivariate regression analysis found that peak SR, reactivity to low-flow and baseline diameter independently contributed to FMD along with sex, diabetes and smoking (R²=0.449). This study demonstrated a SR dose-independence of reactivity to low-flow and also a significant association between reactivity to low-flow and FMD. Furthermore, peak SR, reactivity to low-flow and baseline diameter each independently contributed to FMD, suggesting that these haemodynamic factors may in part determine FMD in BA.