Waiting a few extra minutes before measuring blood pressure has potentially important clinical and research ramifications

Office blood pressure (BP) is recommended to be measured after 5 min of seated rest, but it may decrease for 10 min of seated rest. This study aimed to determine the change (and its clinical relevance) in brachial and central BP from 5 to 10 min of seated rest. Office brachial and central BP (measured after 5 and 10 min), left ventricular (LV) mass index, 7-day home and ambulatory BP were measured in 250 participants with treated hypertension. Office brachial and central BP were significantly lower at 10-min compared with 5-min BP (P<0.001). Seven-day home systolic BP (SBP) was significantly lower than office SBP measured at 5 min (P<0.001), but was similar to office SBP at 10 min (P = 0.511). From 5 to 10 min, the percentage of participants with controlled BP increased and the percentage of participants with high central pulse pressure (PP) decreased (P<0.001). Moreover, brachial and central PP were significantly correlated with LV mass index measured at 10 min (r = 0.171, P = 0.006 and r = 0.139, P = 0.027, respectively), but not at 5 min (r = 0.115, P = 0.068 and r = 0.084, P = 0.185, respectively). BP recorded after 10 min is more representative of true BP control. These findings have relevance to appropriate diagnosis of hypertension and design of clinical trials.