Battery Life in Extreme Conditions
Apple claims 72 hours of battery life in normal use and 36 hours with always-on display. Our 30-day test confirmed these claims with nuance: with always-on display, GPS tracking 3x per week, and continuous heart rate monitoring, we averaged 34 hours between charges. During a 4-hour marathon with continuous GPS and heart rate, battery dropped 22%—leaving enough for a full day afterward.
Sensor Accuracy
We compared the Ultra 3's heart rate sensor against a Polar H10 chest strap during interval training. Average heart rate matched within 2 BPM across all intensities. The new blood pressure monitoring feature (FDA-cleared for trend notifications) showed consistent readings compared to a validated Omron cuff—within 5 mmHg for systolic and 3 mmHg for diastolic.
The depth gauge and water temperature sensor worked accurately during a 30-meter recreational dive. The dive computer mode calculated no-decompression limits consistent with our Suunto backup computer.
Durability
The titanium case survived impacts against rock walls during trail running without scratches. The sapphire crystal remained unmarked after 30 days of daily wear including gym sessions, cooking, and manual labor. The Alpine Loop band showed minimal wear and maintained secure attachment throughout.
Verdict
At $799, the Ultra 3 is overkill for casual users. For endurance athletes, divers, and outdoor enthusiasts who need reliable GPS, accurate sensors, and multi-day battery in a durable package, it's the best smartwatch available. The blood pressure trend feature alone justifies the upgrade from Ultra 2 for health-conscious users.
