Apple Watch Ultra 4 adds a Max Extended Workout mode that Apple rates for up to 45 hours of tracking while keeping GPS sampling at one-second intervals. Apple says the mode is aimed at 100-mile races, and it is the longest workout figure the company has published for any Apple Watch.
It sits above the existing Extended Workout mode, which Ultra 4 now runs for up to 25 hours, 25 percent longer than before. The new mode nearly doubles that number on a watch that costs the same $799 as last year’s Ultra 3.
Max Extended Workout vs the other Apple Watch battery modes
| Mode | Watch | Apple’s figure |
|---|---|---|
| Max Extended Workout | Ultra 4 | Up to 45 hours, one-second GPS |
| Extended Workout | Ultra 4 | Up to 25 hours |
| Normal use | Ultra 4 | Up to 50 hours |
| Low Power Mode | Ultra 4 | Up to 84 hours |
| Outdoor workout | Series 12 | Up to 10 hours |
| Normal use | Ultra 3 | Up to 42 hours |
Why one-second GPS matters for a 100-mile race
A 100-mile trail race commonly takes more than a day, which is longer than the 25-hour Extended Workout rating. Apple’s answer is a mode that reaches 45 hours without lowering the GPS sampling rate, and it pairs that with a claim that Ultra 4 has the most accurate on-device GPS in a sports watch.
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What Apple has not published is what the mode gives up to get there. The release does not say whether heart rate sampling, the display or other sensors are reduced in Max Extended Workout mode, so treat the 45-hour figure as a GPS tracking number until the specifications page explains the rest.
Charging is part of the story for multi-day events. Apple says 15 minutes on the charger gives Ultra 4 18 hours of use, which matters at an aid station or crew stop.
Heart rate, Readiness and recovery for ultra runners
The other half of the endurance pitch is the new Health Sensing System, shared with Apple Watch Series 12. New optical and electrical heart sensors take heart rate every 5 seconds all day and HRV every 5 minutes, and Apple cites a study of more than 1,000 participants that found Apple Watch the most accurate heart rate sensing in a wearable.
Recovery HRV feeds a daily Readiness score from 0 to 10, built from recent activity, training load, vitals and sleep, with four recommendations: Recover, Pace Yourself, Ready or Go For It. It updates during the day.
- Workout Buddy in watchOS 27 works without a nearby iPhone over Wi-Fi or cellular and adds Spanish
- The new Health app in iOS 27 adds Health Age using VO2 max, resting heart rate, sleep and HRV from Apple Watch
- Movement evaluations for flexibility, strength, balance and VO2 max use the iPhone camera and Apple Watch, on device
Apple has not said whether Max Extended Workout mode will reach Ultra 3 through watchOS 27, which supports Ultra 2 and later and arrives as a free update on Monday, September 14 with iOS 27. Ultra 4 is on pre-order today and in stores Friday, September 18, and our event recap covers the rest of the day.
