The deviation between the measurement values of the watch and the
sphygmomanometer is determined by many factors. The measurement part of the sphygmomanometer is in the brachial artery, and the measurement part of
the watch is in the two main public branches of the micro artery.Under normal circumstances, the measurement value of aortic blood pressure and micro arterial blood pressure will differ by 30 to 40. lf you use a watch and a
sphygmomanometer to measure at the same time, since the blood flowing in the artery is in the centrifugal direction, when the sphygmomanometer measures, the lower part of your elbow is under pressure, and the blood
cannot branch smoothly to the artery below. Flow, increased vascular tension, will make the upper and lower blood pressure measurements more deviations.