An evaluation published in October 2026 reports that one Apple Watch Ultra 4 tester had unwanted music changes and one restart while using the touchscreen with sweaty fingers during a run. Apple’s battery figures are mode-specific: up to 50 hours in normal use, 84 hours in Low Power Mode, 25 hours in Extended Workout and 45 hours in Max Extended Workout.
What happened during the reported run
The evaluator described music changing unexpectedly and one restart while using the watch’s touchscreen with sweaty fingers. The same evaluator found the 49 mm case uncomfortable, but found the Action button useful for starting and pausing workouts.
For a separate look at Apple Watch audio features and the legal questions around them, see our earlier coverage.
Apple’s battery figures cover four different modes
Apple’s maximum estimates depend on the selected mode and its settings. The everyday-use tests also use different activity profiles: Apple’s normal-use test included 630 time checks, 190 notifications, 30 minutes of app use, two 60-minute workouts with Bluetooth music and 12 hours of sleep tracking. Its Low Power Mode test included 1,100 time checks, 330 notifications, 55 minutes of app use, two 60-minute workouts with Bluetooth music and 18 hours of sleep tracking.
| Mode | Apple’s stated maximum | Conditions Apple describes |
| Normal use | Up to 50 hours | Test included 630 time checks, 190 notifications, 30 minutes of app use, two 60-minute workouts with Bluetooth music and 12 hours of sleep tracking. |
| Low Power Mode | Up to 84 hours | Test included 1,100 time checks, 330 notifications, 55 minutes of app use, two 60-minute workouts with Bluetooth music and 18 hours of sleep tracking. |
| Extended Workout | Up to 25 hours | Full GPS and heart-rate readings; Low Power Mode turns on during the workout. |
| Max Extended Workout | Up to 45 hours | For outdoor runs, walks and hikes, with GPS readings every second. Low Power Mode is on; alerts and splits are disabled, and some metrics are unavailable. |
Apple says actual battery life varies with use, configuration, cellular network, signal strength and other factors. The longer Max Extended Workout estimate comes with fewer functions: it disables alerts and splits and makes some metrics unavailable.
Fit, controls and training features
Apple announced the Ultra 4 on September 9, 2026, with an S11 chip and redesigned optical and electrical heart-rate sensors. Apple says passive heart-rate readings occur every five seconds throughout the day. Its Readiness feature provides a daily score from 0 to 10 and one of four recommendations, based on recent activity, training load, vitals and sleep score. Apple says the score is intended to inform daily planning, not decide whether exercise is safe.
What the reported measurements say
The evaluation reported initial heart-rate comparisons against a Polar H10. The coefficients describe how closely the readings varied together; they are not percentages of accurate readings.
| Activity | Reported correlation with Polar H10 |
| Indoor cycling | 1.00 |
| Running | 0.94 |
| Weight training | 0.99 |
In a separate test of about 5,000 steps, the reported median difference from a manual count was five steps.
U.S. price and running trade-offs
Apple announced a U.S. starting price of $799. Its September 9 announcement said store availability would begin September 18, 2026.
For runners, the two workout modes have different trade-offs: Extended Workout retains full GPS and heart-rate readings, while Max Extended Workout offers a higher stated maximum with alerts and splits disabled and some metrics unavailable.
