- The diagnostic recommendation for orthostatic hypotension (OH) is to measure blood pressure during the first 3 min after getting up from a lying position. There are no clear definitions as to the amount of time that the patient should lie down before this, and the number of measurements to be taken in lying and standing positions. The aim of this study was to identify the optimal time to measure blood pressure when lying and standing. This was a prospective study of 99 patients aged 65 years and above in an urban primary care clinic. Blood pressure was measured at 1 min intervals over 10 min in the lying position and 7 min standing. OH was found in 37 patients (37.4%). Of these, 56.8% were identified in the 1st minute, 67.6% after 2 min and 83.8% after 3 min of standing. In all cases, participants with OH were asymptomatic. In the lying position, blood pressure stabilized after 7 min, but when the 7th minute was used as a reference for OH many cases were lost. To optimize the identification of OH, blood pressure should be measured at 1 min intervals over the first 3 min after standing up. The amount of time that patients should lie down before blood pressure is measured standing up still has to be determined.