CUPERTINO, California — Cardiologists and technology reviewers questioned the reliability of the Apple Watch Series 12's new hypertension notification feature on Sunday, warning that early users risk both false alarms and false reassurance from the device.

Apple began shipping the Series 12 in September, promoting an expanded health suite that builds on its previously cleared hypertension detection tools. The company has said the feature analyzes sensor data over 30-day periods to flag possible signs of chronic high blood pressure, not to deliver clinical readings.

Reviewers testing the device reported inconsistent notifications and stressed that the watch does not replace a validated cuff. The American Heart Association has previously cautioned that wrist-based optical sensors remain less accurate than standard blood-pressure monitors, particularly for patients with darker skin tones or arrhythmias.

Cardiologists said the volume of first-time users receiving alerts could strain primary care clinics as patients seek follow-up testing. Apple's guidance directs anyone receiving a notification to confirm results with a traditional monitor and consult a physician before altering treatment.

Apple maintains that the feature received regulatory clearance and is designed as a screening aid. A company spokesperson said the hypertension tool was intended to prompt clinical evaluation rather than to diagnose or measure blood pressure directly.