In general, the watch blood pressure measurement is not accurate, there is a certain degree of error.
Most of the current watch/bracelet blood pressure measurement is basically in the form of a sensor, with a certain algorithm to estimate the blood pressure, without any medical proof of its ability to measure accurately.
The basic principle is that the bracelet / watch light to the skin (generally measured blood oxygen occurs red light / infrared light, green light with heart rate), through the skin tissue reflected back to the light is received by the photosensitive sensor and converted into electrical signals and then converted into digital signals, a simple understanding of: light, electricity, digital signals.
The traditional sphygmomanometer using a cuff inflatable, the brachial artery for part of the blood flow blockage, the measurement is a person’s quiet, awake state, the blood pressure of the upper arm, so with the watch to measure blood pressure compared to the watch may produce a certain degree of error.
It is recommended to use traditional blood pressure measuring instruments, such as mercury column or electronic sphygmomanometers for blood pressure measurement under the guidance of a doctor to avoid errors that may delay treatment.