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We're living in the wild world of wearables. Wearable tech companies are constantly launching new features that blur the line between consumer gadgets and medical-grade devices.

This creates significant confusion for both consumers (patients) and physicians.

For example, if WHOOP's blood pressure insight feature indicates you have high blood pressure, should you visit your doctor for evaluation? And should that doctor trust the reading if the device isn't FDA-approved or cleared for blood pressure measurements?

You see, this is confusing!

In this article, I'll highlight Apple Watch and WHOOP's latest "blood pressure" features, share thoughts on where the wearable space is heading, and offer my perspective from both a physician and healthcare system viewpoint.

Apple Watch and WHOOP have recently unveiled new features related to blood pressure, each offering distinct benefits: Apple Watch detects elevated blood pressure, while WHOOP provides an estimate.

Apple Watch's blood pressure feature is a notification system that alerts you to potentially elevated blood pressure without providing an actual measurement. Users must wear the device for 30 days to collect sufficient data for the system to make a prediction.

The blood pressure feature relies on artificial intelligence. The model was trained using photoplethysmography (PPG) data—which measures blood volume changes through the skin—from participants with various blood pressure profiles. Researchers aimed to correlate blood vessel volume data with hypertension indicators.

The model underwent clinical validation in a study with approximately 2,000 participants with diverse baseline blood pressures. Key findings included:

This feature serves as a predictor of elevated blood pressure rather than a diagnostic tool. After receiving a notification, users are instructed to measure their blood pressure with a physician-recommended device (such as OMRON) and record results in Apple Health for proper diagnosis.

Apple has received FDA premarket clearance for this feature, giving it a medical device status. The clearance specifically states it's not intended for diagnosis, treatment monitoring, or blood pressure surveillance, only for alerting users who may need further evaluation. It’s only for those 22 years or older, not pregnant, and have not been diagnosed with hypertension

WHOOP's blood pressure feature, called "Blood Pressure Insights," takes a completely different approach.

Unlike Apple Watch's notification system, Blood Pressure Insights provides actual blood pressure estimates. The feature requires monthly calibration with an accurate home blood pressure monitor. Once calibrated, WHOOP analyzes data including heart rate, HRV, and blood flow patterns during sleep (when you're most relaxed) to estimate your blood pressure each morning.

Similar to Apple Watch, WHOOP employs a machine learning model to estimate blood pressure. Their model is trained on over 32,000 sleep sessions from more than 11,000 members and has been validated against clinical readings (although I can’t find the paper).

However, unlike Apple Watch, WHOOP's Blood Pressure Insights does not have FDA premarket or market clearance (read this article to understand the difference!). The FDA sent a warning letter to WHOOP, stating that because the feature provides actual blood pressure readings, it's considered a medical device requiring FDA approval—which WHOOP launched without obtaining.

WHOOP defended its feature as being for "wellness" and "healthy lifestyle" rather than diagnostic purposes. The FDA disagreed, pointing out that providing blood pressure estimates with color-coded indicators (green, yellow, orange) clearly serves a diagnostic function.

Despite this regulatory challenge, WHOOP continues to offer blood pressure insights.

Back in February 2023 (over two years ago!), I made this prediction:

We're clearly at this point now, which is exciting. However, we need to approach this development carefully.

For consumers (patients), these new blood pressure features can be truly lifesaving—they represent guardian angel technology:

But without proper validation, this technology can cause harm—which is precisely why the FDA issued their notice to WHOOP about its blood pressure insight feature.

Consider this scenario: You're using WHOOP's blood pressure feature. Every morning your readings show around 110/80, and WHOOP displays this in the green zone (good!). A year passes with these reassuring readings. Then during a checkup, your physician measures your blood pressure at 140/90. They prescribe an at-home monitoring kit, which confirms consistent readings of 140/90, despite WHOOP showing lower values. You've unknowingly lived with elevated blood pressure for a year that could have been controlled.

Apple Watch's feature, at least, was clinically validated with a published study reporting specific sensitivity and specificity measures.

As physicians, we must be aware of these wearable features, understand their intended population (e.g., Apple's blood pressure feature is not for everyone with an Apple Watch!), and recognize where they fall on the consumer versus medical-grade spectrum. If a patient presents "well-controlled" blood pressure data from WHOOP, we should approach it with appropriate skepticism!

At a system/population level, Apple Watch's blood pressure feature could have a significant impact. Millions of people wear Apple Watches. Given the specificity of its blood pressure notification feature, we can detect elevated blood pressure in substantially more people, which is remarkable. This is guardian angel technology at work! As physicians, we can intervene earlier with lifestyle modifications and/or medications to reduce cardiovascular risk 10-20 years down the line. Just imagine: if Apple Watch detects elevated blood pressure in a 30-year-old, the potential years added to their life through early risk modification is incredible.

In summary, wearable blood pressure technologies from Apple Watch and WHOOP represent distinctly different approaches—Apple's FDA-cleared notification system (high specificity, lower sensitivity) versus WHOOP's unapproved estimation feature requiring calibration. This exemplifies the blurring line between consumer gadgets and medical devices, creating both opportunities for early intervention and potential risks if readings are inaccurate or misinterpreted in clinical decision-making.

Every internist has been there: a healthy 60-year-old scheduled for cataract surgery ends up with an EKG, labs, maybe even a chest X-ray, all for a procedure that carries almost no systemic risk. We order them not because they’re useful, but because “that’s how it’s always been done.”

These pre-op assessments eat up valuable clinic slots, cost patients over $1,200 in unnecessary testing, and force them to take time off work for visits that add no measurable benefit. Multiply that by tens of thousands of low-risk surgeries every year, and the waste becomes staggering.

But what if we stopped doing them altogether, and replaced the whole process with something smarter?

👉 Full breakdown in my latest Inefficiency Insights article here.

AI Isn’t Coming for Your Job—It’s Coming for Your Paperwork

We spend nearly $5 trillion on healthcare every year—but up to 15% of that is wasted on administrative bloat.

Think: prior auths, claims, referral faxes, and inboxes full of chart reviews. Not care. Just the stuff around it.

AI may finally be the tool to automate that waste away.

But which AI tools are actually moving the needle? What’s hype vs. reality? And how close are we to fully automated workflows like dynamic scheduling, ambient documentation, and claims adjudication?

👉 Full breakdown in my latest Huddle+ article here.

Revenue Cycle Management might sound like dry admin work, but it’s the reason patients get surprise bills, doctors spend hours on paperwork, and hospitals live or die by razor-thin margins.

If you want to understand why U.S. healthcare feels so broken, you have to understand the middleman that moves the money.

👉 Read more details here.

We were trained to take care of patients. But no one ever taught us how the system actually works:

That’s why I built this course: How Healthcare Really Works.

It’s short, visual, and built for people like us — physicians trying to make sense of the business and policy forces shaping our day-to-day work.

👉 Enroll in the course here.