Recent Apple Watch models have a hypertension notification feature. Receiving such a notification does not necessarily mean you have hypertension, but it's important to know how to interpret this alert and what to do next . Does the Apple Watch notification mean the watch measured your blood pressure? No. The feature is not related to a blood pressure measurement, and no value is displayed. It's a screening tool; that is, it analyzes signals from the optical pulse sensor over time (using photoplethysmography), and if it finds patterns consistent with a high probability of high blood pressure, it sends a notification. Therefore, this system does not diagnose high blood pressure . So, how does the watch "get there"? The Apple Watch collects photoplethysmography signals from the wrist throughout the day. An algorithm passively analyzes these signals over 30-day periods. If the pattern exceeds a predefined limit, the user receives an alert. And is the Apple Watch alert reliable? Regarding reliability, it's important to distinguish two concepts: Sensitivity , that is, the ratio of people who actually have high blood pressure to those who were alerted; Specificity , that is, the fact that people who do not have high blood pressure were not alerted. In the clinical validation study presented by Apple, in which Apple Watch results were compared with measurements taken at home with a blood pressure cuff device, the reported performance was approximately: Overall sensitivity ~41%, meaning the watch alerted about 4 out of 10 people who had high blood pressure. In a subgroup of people with more severe hypertension, the sensitivity value was higher; Overall specificity ~92%, meaning that 9 out of 10 people who do not have high blood pressure did not receive an alert. Thus: Receiving an alert does not mean you have a diagnosis of hypertension, but it is relevant information to be confirmed with a validated device; Not receiving an alert does not rule out high blood pressure , because the sensitivity is not high. So, what should I do if I receive a notification? Think of it as a smart reminder to do what the guidelines already recommend: confirm your blood pressure with reliable methods and measurements. In practical terms, recommendations for measuring blood pressure at home include: Use a validated device; Rest for a few minutes before taking the measurement; Use a device with an arm cuff of the appropriate size; Take repeated measurements (not a single measurement); Discard the first result, calculate the average of the following ones, and record it. After you have the results of the measurements taken at home, you should discuss them with your attending physician . Frequently asked questions Remember this… High blood pressure is one of the most important risk factors for stroke, acute myocardial infarction, and kidney failure. In most people, high blood pressure is silent , showing no symptoms for many years. For this reason, early detection of high blood pressure can make all the difference in preventing complications. Symptoms that may be related to high blood pressure should prompt a visit to the doctor . Sources K250507: Hypertension Notification Feature . 2025. Hypertension Notifications Validation Pape . 2025. Mancia G, Kreutz R, Brunström M, et al. 2023 ESH Guidelines for the management of arterial hypertension. J Hypertens 2023;41:1874-2071. Yang E, Schutte AE, Stergiou G, et al. Cuffless blood pressure measurement devices-international perspectives on accuracy and clinical use: a narrative review. JAMA Cardiol 2025;10:624-31. Author : José Ferreira Santos (cardiology) Meet the cardiology clinical team from Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
