Human blood pressure is not a constant parameter. For completely normal physiological reasons, blood pressure can vary up to 30 mmHg over a short period. It is therefore possible for pressure to fluctuate between two measurements. In fact, it is very difficult to take consecutive measurements under the same conditions. This type of test usually gives different results due to the instability of physiological conditions and secondary factors (discussion, noise, movements, etc.). This is why the average of several results, measured on several days at the same time and under comparable conditions, is considered to be the real blood pressure. If, for example, you measure blood pressure one hour after the evening meal over three consecutive days, you will not find significant differences. The average of these results reflects your blood pressure more accurately.
To limit these variations as much as possible, be sure to follow the precautions for use.
*credit to Sylvain of iHealth Labs EU