The emergence of smartwatches with blood pressure monitoring capabilities represents a significant shift in personal health management. Consumers are increasingly seeking convenient, non-invasive alternatives to the traditional upper-arm cuff for tracking cardiovascular health throughout the day. This technology integrates regular blood pressure checks seamlessly into a user’s daily routine, reflecting a growing desire for continuous and easily accessible health data.
How Smartwatches Measure Blood Pressure
Smartwatches use two distinct methods to provide blood pressure readings: actual measurement and estimation. The most accurate approach miniaturizes the established oscillometric method, the same technology found in a standard arm cuff. Devices using this technique incorporate a small, inflatable air bladder within the watch band that physically compresses the artery at the wrist to calculate systolic and diastolic pressure as the air slowly releases.
Most other smartwatches rely on a cuffless method that estimates blood pressure by correlating it with the velocity of the pulse wave. This technique utilizes Photoplethysmography (PPG) and an Electrocardiogram (ECG) sensor. The device calculates the Pulse Transit Time (PTT) by measuring the time it takes for the pulse wave to travel from the heart (detected by the ECG) to the wrist (detected by the PPG). A shorter PTT suggests higher arterial stiffness and, by correlation, higher blood pressure. These devices use proprietary algorithms to convert the PTT measurement into a blood pressure estimate.
Regulatory Approval and Verified Devices
The question of which smartwatches can measure blood pressure is best answered by looking at regulatory clearance, which validates a device’s medical accuracy against established clinical standards. Regulatory bodies like the U.S. Food and Drug Administration (FDA) or European CE Marking require rigorous testing to ensure a device meets specific accuracy protocols before it can be marketed as a medical device. This clearance distinguishes them from general wellness trackers that offer blood pressure estimation without formal validation.
Devices using the physical, inflatable cuff method are the most frequently cleared for medical use, as their technology is a miniaturized version of the gold standard. The Omron HeartGuide, for example, has received FDA clearance for its oscillometric measurement system. The Huawei Watch D, which utilizes an inflatable micro-pump and air bag, has also received regulatory approval in various international markets.
Other popular smartwatches, such as the Samsung Galaxy Watch series, utilize the cuffless PTT estimation method. They have received regulatory clearance in specific regions, including South Korea and Europe, though often not yet in the United States for their blood pressure function. This clearance confirms the device has been clinically tested against standards, such as ISO 81060-2, which dictates the accuracy required for non-invasive sphygmomanometers. Consumers must verify the medical device status in their specific region, as regulatory status varies significantly by country.
Limitations Compared to Traditional Monitoring
The most significant limitation of cuffless blood pressure smartwatches is their mandatory reliance on regular calibration. Users must periodically take a reading with a traditional, validated arm-cuff monitor and enter that value into the watch’s companion app to synchronize the estimation algorithm. If calibration is neglected, the accuracy of the PTT-based reading will drift over time, potentially leading to misleading data.
The accuracy of all wrist-worn devices is highly sensitive to external factors like fit and wrist position. The watch must be worn snugly, and during measurement, the wrist must be held still and at heart level to prevent gravitational effects from skewing the reading. Movement and improper placement can interfere with the optical sensors, introducing “noise” that compromises the PTT calculation. Because of these factors, these smartwatches are intended only for monitoring trends and screening purposes, not for diagnosing hypertension or replacing a physician’s clinical measurement.