Google has added insulin resistance and blood pressure trend tracking to the Fitbit Air and Edge, nudging these devices past the familiar territory of step counts and sleep scores and into the murkier realm of actual health insights. The features arrive under Google's "Health Guardian" suite of proactive safety tools for the Pixel Watch and Fitbit.

There is, of course, a catch. The features are available solely to Google Health Premium subscribers, a $100 annual subscription that also unlocks Google's AI health coach, advanced sleep tracking, and a more expansive selection of health-tracking features. Health insights, it turns out, remain a premium product.

To be clear, the Fitbit does not measure your insulin or glucose outright. Instead, its algorithm analyzes heart rate, activity level, sleep, and other metrics to show changes in metabolic health. The device will also track your blood pressure patterns without a cuff, monitor your pulse whether you're asleep or awake, and, at the end of the month, hand you a set of insights. Eligible Fitbit Air and Fitbit Edge users who have worn their device for five days or more will see this insight in the Health tab of the app.

Similar to blood pressure trends, the insulin resistance feature uses Fitbit sensors to monitor shifts in metabolic health. Insulin resistance is a precursor to type 2 diabetes, so the potential here is genuinely useful - giving users a less invasive way to glimpse changes in their insulin levels. Note the word "trends": this points toward overall patterns rather than a direct diagnosis.

Unlike a continuous glucose monitor, which penetrates the skin and uses blood to gather metabolic data, the insulin resistance feature was built to assess biometric and metabolic patterns through a multimodal model. Google trained that model on data gathered by other wearables as well as compiled demographic data, according to its paper in Nature.

Once the feature detects elevated insulin resistance patterns, it notifies the user to take additional action. Fitbit users can even connect their Abbott CGM to the Google Health app for additional glucose monitoring. And by offering these Health Guardian features to more devices than just its flagship Pixel Watches, Google is giving more users - specifically budget-conscious users who own a $100 or $180 Fitbit Air or Edge - the ability to track and stay ahead of some common and serious health conditions.

The insulin resistance feature is nowhere near the capabilities of a non-invasive CGM, but Google's development of a multimodal model for tracking biometric responses to insulin activity suggests the company is getting closer to that non-invasive reality.

Non-invasive glucose monitoring is like the foldable phone of wearable technology: a product idea that has been around for years, with every tech company racing to deploy its own version, with varying degrees of success and adoption. Even Steve Jobs had dreams of an Apple glucose monitor that people could use - no finger prick necessary. Rumors suggest Apple has also been working on this for years now.

But Google might be a few steps ahead of Apple on this one. Its deployment of insulin resistance trends to new Fitbit devices is one way it is advancing toward a CGM that uses algorithmic AI instead of needles and blood - which, for anyone who has ever winced at a lancet, sounds like progress worth the subscription fee.