1, photoelectric volume pulse wave tracking method
This is the method used by most pedometers to measure heart rate. Simply put, the sensor will emit a beam of light on the skin and then measure it (reflected light or transmitted light).
The blood volume in the skin pulsates under the action of the heart. When the heart contracts, the peripheral blood volume is the largest, the light absorption is also the largest, and the detected light intensity is the smallest. When the heart is relaxed, on the contrary, the detected light intensity is the largest, which makes the light intensity received by the light receiver change in a pulsating manner, thus measuring the pulse. Because red blood cells absorb the most green light, most of these sensors emit green light.
2. ECG signal measurement
The detection principle of this method is similar to ECG. By measuring the change of potential difference between two points on the body surface, the data of ECG activity can be obtained. Although there is no need to connect many electrodes like ECG, two electrodes are enough to measure heart rate.
Comparatively speaking, the second method is more accurate than the first method, but it may not be as good as the first method if the electrode cannot be close to the skin or disturbed by muscle trembling.
Step 3 measure blood pressure
The general pedometer bracelet will not provide the function of measuring blood pressure, because the difficulty and cost of detection will be greatly increased, and the blood pressure measured at the wrist may not be accurate, because it is too far from the aorta, vascular variation, arterial stenosis and blockage will affect the measured value, especially for the elderly.
Is the pedometer watch accurate in measuring blood pressure and heart rate?
The function of pedometer watch to measure blood pressure and heart rate is actually an additional function. After all, we buy pedometer watches mainly for health monitoring and step counting during exercise. As for measuring blood pressure and heart rate, people who basically use pedometer watches will not have much demand for it. Middle-aged and elderly people who have requirements for measuring blood pressure and heart rate will not use pedometer watches to measure. They usually use professional instruments to measure heart rate and blood pressure.
Generally speaking, it is more accurate to measure the heart rate with a pedometer watch, unless there is arrhythmia, such as atrial fibrillation, in most cases, a more accurate heart rate can be measured; However, measuring blood pressure is not accurate, so the general manufacturers of pedometer watches will not increase the function of measuring blood pressure. If there is such a demand, it is more reliable to buy a cuff electronic sphygmomanometer to measure the upper arm.