Apple has opened preorders for the Watch Series 12 and Ultra 4, featuring a new Health Sensing System. The company claims the most accurate heart rate monitoring in any wearable, based on a study of over 1,000 participants. New readiness scores analyze activity, training load, vitals, and sleep to rate daily capacity from 0 to 10.

The iOS Health app will gain a Health Age score using vision-based AI and heart rate data, plus lab testing through Quest Diagnostics with over 50 biomarkers for $119. Apple Intelligence adds features like Live Rewind and Siri Recap. Both watches ship September 18, priced at $399 and $799.