Cuffless smartwatches promise a more convenient way to monitor blood pressure. Unlike traditional blood pressure monitors, they do not inflate or squeeze the arm. In theory, users can simply wear the device and access blood pressure readings whenever needed.
However, the absence of a cuff does not mean that a device can measure blood pressure as independently or consistently as a traditional cuff-based monitor.
In a 2025 scientific statement, the American Heart Association noted that cuffless blood pressure devices have potential, but important uncertainties remain regarding their accuracy, clinical use, and reliability in real-world conditions.
Cuffless Devices Usually Estimate Blood Pressure
Traditional electronic blood pressure monitors use an inflatable cuff. The cuff inflates and deflates while the device detects pressure changes in the artery and calculates systolic and diastolic blood pressure.
Cuffless devices rely on optical sensors and algorithms to estimate blood pressure.
They do not directly detect blood pressure in the same way as an inflatable cuff. Instead, they measure physiological signals that may change along with blood pressure.
Why Do Cuffless Blood Pressure Devices Need Calibration?
Movement, posture, temperature, sensor placement, and individual differences can all affect the signals used by cuffless devices.
For this reason, users often need to take a reading with a traditional upper-arm or wrist blood pressure monitor first. That result is then entered into the smartwatch or app as a reference point for the algorithm. Regular recalibration may also be required.
This raises an important question:
> The purpose of cuffless monitoring is to reduce the inconvenience of using a cuff. But if users still need a traditional cuff-based monitor to obtain reference readings and recalibrate the device, can it really be considered independent cuffless blood pressure measurement?
The device may be cuffless in appearance, but the overall measurement process still depends on a cuff-based blood pressure monitor.
The quality of the calibration may also depend on whether the reference monitor is accurate, whether the user follows the correct measuring position, and whether the calibration procedure is performed properly.
FDA Clearance Does Not Remove Every Limitation
Some cuffless blood pressure devices have received FDA clearance. However, FDA clearance means that the device has completed the applicable regulatory review process. It is not an unlimited guarantee of accuracy for every user and every real-world situation.
The market also includes many smartwatches and smart rings that claim to measure or estimate blood pressure without receiving the appropriate FDA authorization.
In a 2025 safety communication, the FDA warned that inaccurate blood pressure readings may lead to incorrect health decisions, delayed treatment, or inappropriate medication changes.
Before purchasing a blood pressure wearable, consumers should check:
·Whether the blood pressure function itself has received FDA marketing clearance or authorization
·Whether the device measures blood pressure with an inflatable cuff or estimates it through sensors and algorithms
· Whether the product clearly explains its limitations and intended use
How Is a Cuff-Based Blood Pressure Watch Different?
A cuff-based blood pressure watch retains the inflatable structure used in traditional blood pressure measurement. The cuff, miniature pump, and measuring system are simply integrated into a wearable watch.
The KINGYIELD Blood Pressure Watch features an inflatable cuff that allows users to take a blood pressure measurement directly on the wrist. It does not require users to first obtain a reading from another traditional blood pressure monitor and enter that number into the watch for personal calibration.
Users still need to rest quietly, maintain the correct posture, and keep the wrist in the proper position during measurement.
The basic difference is:
> A cuff-based device inflates and deflates to detect pressure changes, while a cuffless device mainly uses sensor signals and algorithms to estimate blood pressure.
Conclusion
Cuffless blood pressure technology has significant potential. In the future, it may make blood pressure monitoring more comfortable, continuous, and convenient.
For now, however, cuffless blood pressure measurement often still depends on calibration with a traditional blood pressure monitor.
When choosing a blood pressure device, do not focus only on marketing terms such as "cuffless" or "smart algorithm." It is more important to understand how the device obtains its readings, whether calibration is required, and whether the blood pressure function itself has undergone the appropriate regulatory review.
For people who need long-term blood pressure management, convenience matters—but accuracy, ability to perform an independent measurement matter even more.
This article is for general health education only and is not a substitute for professional medical advice, diagnosis, or treatment.
