Apple Watch hypertension alerts may miss cases of high blood pressure, with the absence of an alert offering limited reassurance, particularly for older adults, researchers say.
Hypertension, or high blood pressure, occurs when blood consistently pushes too forcefully against artery walls, increasing the risk of heart disease and stroke.
The study applied performance data from the smartwatch’s blood pressure notification feature to US population statistics to estimate how it performs in real-world use.
Researchers found that around 69 per cent of people who received an alert did have hypertension, while about 79 per cent of those who did not receive an alert were free of the condition. Performance varied by age, race and ethnicity.
The feature, cleared by the US Food and Drug Administration last year, is not intended to diagnose hypertension. It uses an optical heart sensor to flag patterns that may suggest raised blood pressure. A validation study submitted to the regulator showed that roughly 41 per cent of people with undiagnosed hypertension received an alert, while nearly 59 per cent did not. Among people without hypertension, 7.7 per cent received an inappropriate alert.
The analysis was carried out by researchers at the University of Pennsylvania and the University of Utah.
In groups where undiagnosed hypertension is more common, alerts were more likely to reflect true hypertension, while the absence of an alert was less reassuring.
For adults aged 60 and older, receiving an alert increased the probability of having hypertension from 45 per cent to 81 per cent. However, those in this age group who did not receive an alert still had a 34 per cent probability of having undiagnosed hypertension.
Performance also differed by race and ethnicity, reflecting wider disparities in cardiovascular health linked to social factors. Among non-Hispanic Black adults, an alert increased the probability of hypertension from 36 per cent to 75 per cent, while the absence of an alert lowered it to 26 per cent.
Jordana Cohen, the study’s lead author and an associate professor of medicine and epidemiology at the University of Pennsylvania School of Medicine, wrote: “However, the absence of an alert provides limited reassurance, particularly in older and higher-risk adults, and routine blood pressure measurement with validated cuff-based devices remains essential.”
The researchers added that while the feature could help many people unaware they have hypertension, “an even larger proportion of individuals with undiagnosed hypertension could receive no alert at all.”
They cautioned that false reassurance may lead to missed opportunities for early detection and treatment, adding: “Rigorous validation, strategies to improve cuffless device accuracy, and thoughtful integration into population screening will be essential if cuffless technologies are to contribute meaningfully to hypertension detection.”