Apple Watch for Hypertension Screening: Accuracy & Impact on Detection Rates
- Routine blood pressure screening with a traditional cuff is recommended for all adults, but a new analysis suggests that the Apple Watch, with its hypertension notification feature, offers...
- Food and Drug Administration (FDA) in September 2025, uses an optical sensor called photoplethysmography to detect patterns in blood flow.
- A validation study conducted by Apple itself found that the watch correctly alerted 41.2% of individuals with undiagnosed hypertension.
Routine blood pressure screening with a traditional cuff is recommended for all adults, but a new analysis suggests that the Apple Watch, with its hypertension notification feature, offers a potentially accessible avenue for broader screening. However, researchers caution that the technology isn’t foolproof and could lead to both false reassurance and unnecessary anxiety.
The Apple Watch feature, cleared by the U.S. Food and Drug Administration (FDA) in , uses an optical sensor called photoplethysmography to detect patterns in blood flow. It then alerts users to the possibility of hypertension, prompting them to seek further evaluation. The device does not directly measure blood pressure.
A validation study conducted by Apple itself found that the watch correctly alerted 41.2% of individuals with undiagnosed hypertension. However, it missed hypertension in 58.8% of those who had it. Conversely, among individuals without hypertension, the watch generated an inappropriate alert in 7.7% of cases, while correctly identifying the absence of hypertension in 92.3%.
These performance characteristics translate to a positive likelihood ratio of 5.35, indicating moderate evidence to support a diagnosis of hypertension when the watch triggers an alert. The negative likelihood ratio is 0.64, suggesting weak evidence to rule out hypertension when no alert is given, according to the study authors.
Researchers from the University of Utah and the University of Pennsylvania sought to determine the real-world impact of the Apple Watch’s hypertension notification feature if it were widely deployed across the U.S. Population. They analyzed data from the National Health and Nutrition Examination Survey (NHANES) spanning to , a nationally representative cohort.
Their analysis included 3,983 participants aged 22 and older, excluding pregnant individuals and those with a known diagnosis of hypertension or who were already taking antihypertensive medication. Based on the estimated prevalence of hypertension in the eligible population, the researchers calculated a positive predictive value of 69.1% for the Apple Watch feature and a negative predictive value of 79.0%.
So that in a population where an estimated 30% have hypertension, an alert from the Apple Watch increases the probability of having the condition to 69.1%. Conversely, the absence of an alert lowers the probability to 21%.
“A large proportion of people unaware they have hypertension could be alerted by this tool,” the authors wrote. “However, an even larger proportion of people with undiagnosed hypertension could receive no alert at all.”
While Apple states that the device is not intended to diagnose hypertension and is designed to encourage users to seek clinical evaluation if an alert is triggered, the researchers express concern that false reassurance could deter some individuals with undiagnosed hypertension from seeking appropriate screening or entering the healthcare system. This could delay detection and treatment.
“High blood pressure is what we call a silent killer,” said Adam Bress, Pharm.D., M.S., a researcher at the University of Utah. “You can’t feel it for the most part. You don’t know you have it. It’s asymptomatic, and it’s the leading modifiable cause of heart disease.”
The study, published in in the Journal of the American Medical Association, highlights the need for rigorous validation, strategies to improve the accuracy of cuffless blood pressure monitoring devices, and thoughtful integration into population-based screening programs if these technologies are to contribute meaningfully to hypertension detection.
The authors conclude that for devices like the Apple Watch to significantly improve hypertension detection, further research and refinement are essential. This includes improving the precision of the technology and carefully considering how it can be best incorporated into existing public health initiatives.