The VivoWatch BP uses two types of sensors to measure blood pressure. Dual photoplethysmography (PPG) and electrocardiography (ECG) sensors mounted on both the watch case front and back add to its versatility. The inside sensors make contact with the wrist and the front sensors work with a finger press.
Asus combines ECG and PPG sensor data to derive accurate blood pressure measurements, supported by an A.I. machine-learning-based algorithm.
ECG sensors measure electrical signals that indicate heartbeat strength and timing. PPG optical sensors measure the relative amounts of reflected light from the skin. The amount of reflected light changes as blood vessels and capillaries expand from greater blood volume when the heart beats and contract when blood volume decreases between beats.
Pulse transit time (PTT), also known as pulse wave transit time (PWTT), is a valid and well-accepted measure of blood pressure that uses ECG-PPG heartbeat signal pairs.
The Asus algorithm translates the sensor data into a systolic blood pressure reading (the first number) when the heart muscle contracts or “beats,” diastolic pressure (the second number) between beats, and heart rate or pulse, measured in beats-per-minute (BPM).
According to Asus, the VivoWatch BP can provide accurate blood pressure readings in just 15 seconds. Depending on how users configure the smartwatch, they will be able to monitor their blood pressure at fixed intervals or at set times during the day. The smartwatch can even read blood pressure while people sleep — assuming they wear the watch.
In addition to reading blood pressure, the VivoWatch BP can track sleep and activity, the latter measured in steps.
The primary purpose of Asus HealthAI software is to give blood pressure management tips. Based on time with the VivoWatch BP sample at Computex, Engadget reports the advice HealthAI provides is “mainly by recommending the number of steps and sleeping hours you need daily.”
The original VivoWatch had a 10-day battery life per charge, but the new version runs for 28 days, according to Asus.
The Asus VivoWatch BP U.S. retail price will be $169, according to Engadget. Pending FDA approval, the VivoWatch BP will be available for sale in the U.S. in 2019. Sales in Asia start this July.