Timed to the launch of its Fitness+ service, Apple has also launched some new features for the Apple Watch.

Starting with iOS 14.3 and watchOS 7.2, the Apple Watch will monitor a user's cardiorespiratory fitness levels.

Prior to this update, the Watch measured VO2 max (the maximum amount of oxygen the body can use during exercise, typically a measurement of someone's fitness level), but only for average and higher levels. Now, Apple Watch will also estimate lower levels, giving less active users a more complete picture of their overall fitness.

To do this, the Watch uses multiple sensors, such as the optical heart sensor, GPS, and the accelerometer. Apple says this is a breakthrough as measuring VO2 max accurately typically requires clinical testing with specialized equipment.

"Cardio fitness is increasingly recognized as a powerful predictor of overall health, and with today's update to watchOS 7, we are making it even more accessible to more people," said Jeff Williams, Apple’s chief operating officer.

To turn on notifications for this feature, users can go to the Health app on their iPhones.

Related Video: Exercise equipment that helps you work out while working from home