Most useful bit of the announcement, coming to all Google wearables it seems:

Blood pressure, sleep breathing, and insulin sensitivity trends

  > Built on state-of-the-art Health Foundation Models trained on billions of minutes of sensor data from opted-in users and rigorously validated against gold-standard clinical measurements, these models power three new monthly trend summaries: blood pressure trends, sleep breathing quality trends, and insulin resistance trends. Rolling out soon — with your first detailed summary arriving after one month of wear — these reports illuminate metabolic, respiratory and cardiovascular shifts early, giving you clear insights to help you take control of your long-term health. Plus, monthly summaries will soon be available across our wearable portfolio, including the new Google Fitbit Air.