Google rolled out Health Guardian to Fitbit Air users this fall, adding blood pressure and insulin resistance tracking to the Google Health app. Pixel Watch 3, 4, and 5 users received these features for free starting in late September. Fitbit Air users can access them through a Google Health Premium subscription at $9.99 per month.
Insulin resistance signals how well your body responds to insulin and can indicate risk for type 2 diabetes. Google notes the insulin resistance feature is "not intended for medical purposes" and "not a pre-screener for diabetes." The company published a research paper on its insulin resistance algorithm, which tracks heart rate, heart rate variability, and activity levels from your watch. However, the paper does not explain exactly how the algorithm works or whether it will be useful across different populations.
Google also published a paper on its blood pressure algorithm, which is not peer-reviewed. The study suggests Google's model performs similarly to clinical blood pressure measurements, though it excluded people with heart disease and its real-world usefulness remains unclear.
To receive monthly reports, Fitbit users must wear their watch for five consecutive days per month for blood pressure data and seven days and nights, non-consecutive, for insulin resistance data. Your first report arrives on the first of the following month. The features launched in Google Health version 5.11 for both Android and iOS.
Actual medical diagnosis requires bloodwork. If you have concerns about insulin resistance or pre-diabetes, talk with a healthcare professional about which tests they recommend and how to interpret results.