Apple releases Hypertension (high blood pressure) Notifications Validation Paper.

I was waiting for this paper.

I didn’t see it on Apple’s Health website before and didn’t get search results for it when searching online, but it’s there now. The google search dates the validation paper with an August 12, 2025 date.

Apple’s main endpoints for this study:

The validation study assessed the following coprimary safety and effectiveness endpoints:

• Notification sensitivity for participants with a Stage 1 or Stage 2 reference hypertension (HTN) category

• Notification specificity for participants with a Normal or Elevated reference HTN category

In more simple terms, for Stage 1 and Stage 2 hypertension, Apple was focusing on making sure a notification was given when a person actually has hypertension (true positive). For people with Normal or Elevated readings that don’t classify as hypertension, Apple was focused on making sure these people did not get a notification of hypertension (true negative).

Apple’s conclusions - If you have Stage 1 or Stage 2 hypertension, you are 41.2% likely to get a notification with a correct diagnosis (true positive). That number is close to 54% if you have Stage 2 hypertension. Generally speaking, the worse your hypertension, the more likely you’ll be notified.

On the flip side, if you have Normal or Elevated blood pressure that’s not classified as hypertension, you are 92.3% likely not to get notified (true negative). That number jumps to 95.3% if you just factor in Normal blood pressure. The more normal your blood pressure, the less likely you’ll be falsely notified.

The basic takeaway: if your Apple Watch tells you your blood pressure might be high, it probably is high and you should follow up with your doctor. If you don’t get any notifications, that doesn’t mean you don’t have high blood pressure because about half the time, Apple Watch doesn’t have enough data to confidently say you do have high blood pressure.

I’m hoping in the future, now that AirPods Pro 3 also have heart rate sensors, we can get more accurate data and higher sensitivity from more measurement sites that makes these tools even more useful as health-aids.

Right now the Apple Watch is nowhere near the greatest tool for detecting high blood pressure, but it sure as hell is a nice backup to have, right on your wrist.

More details in the paper.