Apple in watchOS 7 and iOS 14.3 added a new cardio fitness feature that lets Apple Watch owners keep track of their cardio fitness levels through VO2 max measurements. VO2 max is the maximum amount of oxygen that the body can use during exercise, and it can be improved through physical activity.
Prior to watchOS 7.2, the Apple Watch was only able to estimate higher levels of VO2 max with outdoor walks, runs, or hikes, but now it can also take cardio fitness measurements as users walk throughout the day, allowing those who don't engage in vigorous exercise to see their cardio fitness levels.
Apple measures cardio fitness levels as high, above average, below average, or low relative to people in your same age group and of the same sex, and it needs to be set up in the Health app on iPhone. Here's how:
- Open the Health app.
- Tap the Browse tab at the bottom.
- Search for Cardio Fitness.
- Scroll down to Cardio Fitness Levels.
- Tap on "Set Up."
- Confirm your health details and enter medications you take that might affect heart rate like beta blockers.
- Tap through to learn about Cardio Fitness.
- Tap "Turn on Notifications" if you want to receive notifications when your cardio fitness level is low. Otherwise, tap "Not Now."
- Tap "Done."
That's all there is to it. From there, the Apple Watch will take cardio fitness measurements during outdoor runs or walks, with the info then aggregated inside the Health app. If cardio fitness levels fall too low and notifications are enabled, the Apple Watch will send notifications with suggestions on how to improve it.
Apple says that there are multiple factors that can lower cardio fitness levels including age, pregnancy, chronic lung conditions, heart conditions, medications, and illness or injury, which is something to be aware of.
Aerobic exercise that causes the heart rate to rise and makes you breathe hard will give you the biggest boost to cardio fitness. Apple recommends running, cycling, or high-intensity interval training, but says even just adding a few hills to a daily walk helps.