Cat Bowen reported that Apple Watch Ultra 4 acquired GPS quickly but recorded distances 1–1.5% long during her runs. Her Runner’s World review, published October 14, 2026, also found larger differences from her Holter monitor during harder runs than during easy activity. The two results measure different things: a quick GPS lock does not settle how accurately a run’s distance is recorded.
GPS lock and distance are different results
Bowen reported a 1–1.5% distance overread in her running tests. At 3.1 miles, that rate works out to about 164–246 feet—an arithmetic illustration, not a separate run result.
Heart-rate readings changed with effort
In Bowen’s Holter comparison, Apple Watch Ultra 4 readings differed by 2–3 beats per minute during steady activity, walking and easy jogging, and by 5–7 bpm during harder running. Bowen says a chest strap is preferable for serious high-intensity heart-rate-zone training.
A separate Xataka review describes a different comparison, against a chest strap: the watch’s optical heart-rate trace followed it closely during easy running, while peaks lagged during intervals. The reviewer also reported 10–20-second gaps in raw data when the watch rejected readings it did not trust (Xataka’s review). These observations use different reference devices and activities, so they describe separate test conditions.
Workout endurance depends on the mode
Apple lists outdoor-workout battery ceilings of up to 18 hours in standard tracking, 25 hours in Extended Workout and 45 hours in Max Extended Workout (Apple’s announcement). The longer modes reduce features: Xataka reports that Extended Workout drops running-technique metrics, while Max Extended Workout lowers heart-rate display frequency and omits custom workouts. Apple’s Max Extended Workout test uses Low Power Mode, disables alerts and splits, and leaves some metrics unavailable.
| Workout mode | Apple-stated maximum | Conditions and feature trade-offs |
| Standard outdoor workout | Up to 18 hours | Standard workout tracking. |
| Extended Workout | Up to 25 hours | Xataka reports that running-technique metrics are omitted. |
| Max Extended Workout | Up to 45 hours | Uses Low Power Mode; alerts and splits are disabled and some metrics are unavailable. Xataka also reports reduced heart-rate display frequency and no custom workouts. |
Running trade-offs Bowen describes
Bowen found the 49 mm watch heavy on long runs and removed it for ultra-distance running. She also noted that lactate-threshold data were absent and that offline mapping was not straightforward. For the broader battery and day-to-day-use context, see NeoTeo’s earlier Apple Watch Ultra 4 coverage.
