Quality control will be achieved by central training and certification of all technicians, ensuring that study personnel follow all protocol elements, including approaches for measuring the participant’s arm and placing the cuff. Use of a calibrated, automated BP monitoring device will minimize technician variability in identifying Kortokoff sounds. Although such measurements may not agree completely with measurements made by a random zero sphygmomanometer, use of a mercury device is no longer permissible; an automated device minimizes technician variability, optimizing consistency across the study. To optimize accuracy, at the beginning of the study, and then monthly, the monitor will be checked by the department of clinical engineering for