Smartwatch Blood Pressure Monitoring: Insufficient Reliability for Clinical Use
Yes, multiple recent studies demonstrate that smartwatches are unreliable for blood pressure measurements and should not be used for clinical decision-making. The evidence consistently shows these devices fail to meet established accuracy standards and exhibit systematic measurement errors.
Key Evidence of Unreliability
Validation Failures
The most authoritative guidance comes from American Heart Association guidelines, which clearly state that wrist monitors have failed most validation studies and are not generally recommended for routine clinical use 1. Finger monitors are even worse—they have been found to be "very inaccurate and should not be used" 1.
Recent Research Confirms Poor Performance
The strongest recent evidence comes from a 2024 validation study that tested three wrist-based devices (Bpro G2, Omron HeartGuide, and Heartisans) against gold-standard measurements 2. None of the three devices passed the ISO81060-2 protocol criteria due to insufficient reliability, despite having mean values within 5 mmHg of reference measurements. The Omron device systematically underestimated systolic BP by 8.46 mmHg and diastolic BP by 2.53 mmHg.
A 2022 study of the Samsung Galaxy Watch Active 2 revealed a systematic bias where low blood pressures are overestimated and high blood pressures are underestimated—exactly the opposite of what you need for detecting hypertension 3. The device showed 83% sensitivity but only 41% specificity for detecting hypertension, making it unreliable for screening.
Specific Device Failures
- Everlast smartwatch: Deviated 16.9 mmHg for systolic and 8.3 mmHg for diastolic BP—far exceeding acceptable limits 4, 5
- BodiMetrics Performance Monitor: Deviated 5.3 mmHg for systolic BP, failing accuracy guidelines 4, 5
- Huawei Watch D: Showed moderate concordance in hypertensive patients but unreliable specificity in normotensive patients 6
Why Smartwatches Fail
Technical Limitations
- Position sensitivity: Wrist must be held precisely at heart level, increasing error potential 1
- Calibration drift: Even devices meeting initial standards show declining accuracy as measurements diverge from calibration points 7
- Individual variability: Devices passing validation can still have errors >5 mmHg in substantial numbers of individual patients, particularly in elderly or diabetic populations 1
Lack of Proper Validation
The guidelines emphasize that only devices validated according to AAMI or BHS protocols should be used 1. Most smartwatches on the market have never undergone proper validation, and many that have been tested have failed 8, 9.
Clinical Implications
What This Means for Practice
- Do not use smartwatch BP readings for diagnosing hypertension or adjusting medications
- Do not accept patient-reported smartwatch BP values without cuff-based confirmation
- Upper arm oscillometric monitors remain the gold standard for home monitoring 1
- Each home monitor should be validated against office measurements before accepting readings 1
Common Pitfalls to Avoid
- Assuming FDA or CE clearance equals clinical accuracy—regulatory approval doesn't guarantee adequate validation 3
- Trusting trend data without understanding systematic bias can lead to inappropriate treatment decisions 3
- Using these devices in populations where they're least accurate (elderly, diabetic patients) 1
The Bottom Line
A 2026 expert review states plainly: "at the present time there is no convincing evidence that any cuffless BP technology has adequate accuracy as required for clinical use, and scientific societies do not recommend them" 10. While these devices may eventually have a role in detecting undiagnosed hypertension for screening purposes, they require confirmation by cuff-based measurement and cannot be used for monitoring treated hypertensives 10.
For any clinical decision regarding blood pressure—whether diagnosis, treatment initiation, or medication adjustment—use only validated upper arm cuff-based oscillometric devices 1. Smartwatches may track trends but cannot replace proper BP measurement equipment.