There are relatively few products that use smart bracelets and smart watches to measure blood pressure, because the detection difficulty and cost will greatly increase.

Regardless of their measurement principle, I personally don't trust their measurement results. Because of work, we often use electronic sphygmomanometer. I found that even the special wrist electronic sphygmomanometer often measures some unreliable results because of too many interference factors.

Even if the blood pressure at the wrist can be accurately measured, it often does not necessarily reflect the real blood pressure in the patient's aorta. Because it is too far from the aorta, the variation of blood vessels, stenosis and blockage of arteries will affect the measured values, especially in the elderly.

Summary: The smart bracelet is used to count the pulse and know the heart rate, which is basically reliable. But if there is arrhythmia, such as atrial fibrillation, it is not necessarily.

Smart bracelets are used to measure blood pressure just for fun. If you want to know your accurate blood pressure, you'd better buy a cuff electronic sphygmomanometer to measure your upper arm.