Apple Watch Ultra 4 introduces a redesigned approach to heart-rate monitoring, with the new model capable of taking a heart-rate measurement every five seconds throughout the day.
The change is part of Apple’s new Health Sensing System, which combines redesigned optical and electrical heart sensors with the S11 chip. Apple describes the system as delivering the most accurate heart-rate sensing in a wearable.
According to Apple, the optical sensor uses larger, more power-efficient green LEDs, allowing Ultra 4 to collect substantially more frequent readings without sacrificing the longer battery life offered by the new model.
The increased frequency means users can see a more current heart-rate reading throughout the day, including through a new heart-rate complication on the watch face. Apple says the additional measurements should also improve the accuracy of Exercise and Move Activity rings.
Heart rate variability monitoring has been expanded too. Ultra 4 measures HRV up to 24 times more frequently and separates the information into Recovery HRV and overall HRV, giving users different views of short-term recovery and longer-term health trends.
Overnight Vitals now incorporates Recovery HRV measurements against the user’s personal baseline, while a new daytime Vitals view can help identify changes in metrics before they become visible in overnight readings.
The richer health data also feeds into Readiness, another major Ultra 4 addition. Readiness considers recent activity, training load, vitals and sleep to generate a daily score and recommendation about the user’s capacity for activity.
Apple says its heart-rate accuracy claims are based on a study involving more than 1,000 participants in which Apple Watch was compared with other leading wearables.
Apple Watch Ultra 4 starts at $799 and is available to pre-order now ahead of its Friday, September 18 release.