Apple Watch Ultra 4 reviews praise battery life and heart-rate accuracy

Reviewers praised the Apple Watch Ultra 4 for its endurance and accurate heart-rate tracking. Testers got two to three days of use with heavy workouts, and a 15-minute charge adds up to 18 hours of battery life. The new Health Sensing System measures heart rate every five seconds throughout the day.

• Up to 50 hours of normal use and up to 84 hours in Low Power Mode
• A 15-minute charge delivers up to 18 hours of battery life
• Heart rate is measured every 5 seconds all day, not just during workouts
• Starts at $799 with a 49 mm titanium case and 3,000-nit display