The X-Wrist Watches use Pulse Transit Time (PTT) to measure your blood pressure using two sensors on the watch:
Electrocardiogram (ECG) sensor
Optical Heart Rate (PPG) sensor
Using these two sensors, the watch calculates Pulse Transit Time - the time it takes for a pulse to travel from the heart to the wrist. The pulse travels faster if blood pressure is higher and slower if blood pressure is lower.
To obtain an exact blood pressure value, calibration with a validated blood pressure monitor is needed ( you can do this at your doctor's office or if you have a blood pressure monitor at home).
Pulse transit time and its corresponding blood pressure value is different for each individual, therefore calibration ensures that blood pressure measurements are accurate to your unique physiology.
HOW TO SET IT UP IN THE MOBILE APP
After you measure your blood pressure with a validated medical monitor, you will then choose the correct setting for your blood pressure type by navigating to
"Explore" →"Settings"→"Watch Settings"→"Your blood pressure range"
Then choosing the correct range* for you:
Lower (<90 sys / <60 di)
Normal (90-120 sys / 60-80 di)
Slightly high (120-139 sys / 80-89 di)
Moderately high (140-159 sys / 90-99 di)
Very high (>160 sys / >100 di)
The watch automatically measures your vitals at the interval you set it.
Warning: Measuring more frequently drains the battery faster. Using the watch to take your vitals every 10 minutes will make your battery last less than 5 days.
*This range is provided to you by your doctor. You need to take different tests over the course of 2-3 days with a certified medical device and input your exact range inside the X-Wrist app so the watch can be calibrated to your body type.
After you choose the correct range of your blood pressure, you must press on the "Calibrate Blood Pressure" button and follow the instructions there.
Complete your last 3 measurements taken by a certified medical blood pressure monitoring device (e.g. like Omron).
Then press on "Confirm calibration" so the device will start a blood pressure measurement and will display the results on the watch screen.
The watch uses a baseline for blood pressure monitoring.
For example: If you have a blood pressure that falls between that range or a high discrepancy between your blood pressure measurements, the watch will not give you the EXACT blood pressure range BUT it will give you an early warning that your blood pressure is high or low by displaying the result is Higher / Lower / Normal compared to the blood pressure range you've inputted.
It is recommended that you ask your medic what your "normal" blood pressure and use that.
Also make sure you've set up your user profile correctly. (this contributes to the accuracy of measuring all health & fitness related activities using the wearable).
Be sure to chose your correct skin color. If you wear the watch over a tattoo chose the darkest dot.
You can follow the link below to see how you can set up your user profile: