Apple Watch Ultra 4 improves battery, GPS and heart tracking

Apple’s Watch Ultra 4 improves the features runners encounter on nearly every outing: satellite connection, battery endurance and pulse tracking. The reviewer saw GPS become ready quickly across parks, wooded streets and areas surrounded by tall buildings. Distance totals remained imperfect, running 1 to 1.5 percent above the comparison distance. That difference may barely register on an easy 5K, but it can affect pace-focused sessions and marathon totals.

Heart-rate results were strongest during walks, relaxed runs and steady exercise. The gap from an external Holter monitor was two to three beats per minute in those conditions. At greater intensity, the difference expanded to five to seven beats per minute. Garmin’s Fenix 9 Pro came closer during hard efforts, differing by three to six beats per minute. Apple also gathers pulse data roughly every five seconds during the day, compared with Garmin’s every single second, giving Garmin a denser record for studying recovery patterns.

Battery performance was another substantial change. Apple’s GPS estimate is two full days, while the reviewer reached three days despite heavy use. Charging was also much faster. The upgraded ECG, hypertension notifications and clearer health app add useful screening information, though they do not provide medical diagnoses or replace a doctor. Cycle information was also described as accurate and helpful for understanding training alongside menstruation or perimenopause.