Google has started rolling out its Health Guardian trend features to the Fitbit Air through version 5.11 of the Google Health app, extending blood pressure and insulin resistance trends beyond the Pixel Watch 3, 4 and 5. On the Fitbit Air the features require a paid Google Health Premium subscription, according to reports from Droid Life and Jetstream that cite Google’s release notes, published Oct. 23, with the update reaching Android and iOS users gradually over about a week.

Health Guardian is Google’s name for what the company calls “proactive health and safety tools” that run in the background and track physiological changes over weeks rather than taking spot readings. Google first switched the features on for Pixel Watch owners in late September, free of charge, with the first monthly reports due in early October, according to a blog post by Shamira Sridharan Weaver, a senior product manager at Google.

What the 5.11 update adds

Fitbit Air wearers with Premium can now set up two of the three Health Guardian trends: blood pressure trends and insulin resistance trends. Sleep breathing quality, the third Pixel Watch feature, is not listed for the Fitbit Air in reports of the update. Blood pressure trends require wearing the tracker for five or more consecutive days in October, and insulin resistance trends require seven or more days and nights, with the first monthly summary arriving at the beginning of November, Jetstream and Droid Life reported.

The update also expands automatic activity tracking from about 10 detectable activity types to as many as 100, including strength training and swimming. Google says contextual reasoning drawn from a user’s routines and history makes detections “nearly 2x more accurate” and cuts missed workouts by more than half, Droid Life reported. Workouts of 15 minutes or longer with a sustained elevated heart rate are logged automatically. The activity changes apply to the Fitbit Air and the Pixel Watch 3, 4 and 5, with the Fitbit Edge due to get them when it went on sale Oct. 27. Elsewhere in the app, “blood glucose” is renamed “glucose,” users can set custom time-in-range goals for a connected continuous glucose monitor, and sleep tracking now uses step data to catch short awakenings.

Wellness trends, not cleared diagnostics

None of the three trend features is a cleared medical device function, and Google says so in its own footnotes. The company describes blood pressure trends, insulin resistance trends and the sleep breathing quality metric as “intended for general wellness and informational purposes only” and “not intended to diagnose, treat, cure, or prevent any medical condition.” The footnote adds that the trends “are not a prescreener for diabetes, hypertension, or sleep apnea respectively,” “do not provide real-time clinical readings,” and “should not be used to adjust medications or treatment plans, or used by individuals who are pregnant.”

One Health Guardian feature does carry a regulatory marking. Breathing Emergency Detection, available on the Pixel Watch 4 and 5 in select European countries, is “designed to automatically prompt a call to emergency services if a user experiences severe drops in blood oxygen,” Google says. The company states that the product “has been CE marked in the EU” but that the feature “has not been cleared or evaluated by the FDA.”

Google has not announced new sensors for any of the trends. According to How-To Geek, Google says the features rely on what it calls Health Foundation Models, with the blood pressure model built on “billions of minutes of raw heart and movement data” and the insulin resistance model trained on “more than a trillion data points from over five million users.” Google Health Premium costs $9.99 a month or $99.99 a year, according to BGR.

Why it matters

Monthly trend reports on blood pressure and insulin resistance move consumer wearables into territory normally occupied by cuffs and blood tests, and the disclaimers matter as much as the features. A report that a user’s trend has shifted is not a blood pressure reading and not a diabetes screen, and Google’s own wording says it should not change how anyone takes medication.

The split between free Pixel Watch access and paid Fitbit Air access also shows how Google intends to monetize its Fitbit line. The screenless Fitbit Air needs a Premium subscription for the same trends that come free with a Pixel Watch, and the same subscription is the gateway to Google’s Gemini-based Health Coach, according to BGR.

What to watch

Fitbit Air users who set up the trends in October should receive their first monthly summary at the start of November. Google has not said whether sleep breathing quality or Breathing Emergency Detection will come to Fitbit devices, or whether the European safety feature will be submitted for FDA review.

The caveats

Google has not published peer-reviewed validation data for the blood pressure or insulin resistance trends, and the “billions of minutes” and “trillion data points” figures are company claims as reported by How-To Geek. The details of version 5.11 come from Google’s release notes as summarized by Droid Life and Jetstream.

This article is for general information and does not replace advice from a qualified clinician. Corrections: email the editor using the address on the Contact page.