Apple Watch Series 12 now checks your heart rate every five seconds

Apple Watch Series 12 introduces a major change to everyday heart-rate monitoring, with the new model now checking a user’s heart rate every five seconds throughout the day.

The improvement is part of Apple’s new Health Sensing System, which combines redesigned optical and electrical heart sensors with the S11 chip. Apple says the system delivers its most accurate heart-rate sensing in a wearable to date.

Larger, more power-efficient green LEDs allow Series 12 to collect heart-rate measurements far more frequently than previous generations, giving the watch a denser stream of data for fitness, activity and health trends.

The Apple Post previously reported that Apple was preparing a stronger focus on continuous health monitoring for Series 12, and the final hardware goes significantly further than the existing approach.

Heart rate variability is also measured up to 24 times more often. Apple has split HRV into two views: Recovery HRV, intended to highlight daily stress and recovery signals, and Overall HRV, which is designed to show broader health trends.

The higher-frequency readings feed into updated Vitals experiences. Overnight Vitals now includes Recovery HRV against a user’s personal baseline, while a new daytime view can surface changes that may appear before overnight measurements would normally catch them.

Apple has also added a new heart-rate complication so users can see their current reading directly on the watch face. The extra data is used to improve Exercise and Move ring accuracy as well.

As announced by Apple, the company tested the new heart-rate system in a study involving more than 1,000 participants and says Series 12 achieved the highest accuracy among the wearables it compared.