If you need to measure blood pressure twice in a row, you only need an interval of about 1-2 minutes. In general, inaccurate blood pressure measurement occurs mainly because the position of the patient measuring blood pressure is not at the same level as the sphygmomanometer, the air in the cuff is not released cleanly, the cuff position is not accurate, etc. If these factors are ruled out, the arm can be changed to measure. If the difference between the two upper limbs is large, it is due to stenosis and plaque in the subclavian artery, which requires timely hospitalization and, if necessary, interventional treatment in vascular surgery. Normally, when measuring blood pressure, we should pay attention to the person whose blood pressure is being measured to remain stationary for at least 5 minutes, the lower edge of the cuff should be about 2 cm above the elbow bend, and the cuff should be loosened and tightened appropriately, while the person measuring blood pressure should also pay attention to the auscultation problem, and under normal circumstances, a pulse pressure difference of about 10 mmHg is normal.