A new Apple Watch alert tells you how fit (or unfit) you are. Here’s how to get it

Vanessa Hand Orellana / CNET

The Apple Watch is about to give you an honest review of your fitness levels. At a time when many of us work from home or they do not have access to gymsFitness trackers like the Apple Watch have helped us keep tabs on how much (or how little) we exercise each day. Now he is translating that data into an evaluation. The watch software update to WatchOS 7.2, available now, brings a new cardio fitness score that uses your VO2 max (or maximum oxygen uptake during exercise) to measure your cardiorespiratory health or aerobic endurance .

Read more: Apple Fitness Plus is a workout routine that’s right for you

Cardio fitness explained

VO2 max is considered the gold standard for determining cardiorespiratory fitness and can be a good indicator of your overall health. Elite athletes use this metric for training purposes to measure endurance, but its effects go beyond exercise. People with low levels of cardio fitness are at greater risk for chronic health problems like heart disease, type 2 diabetes, colon and lung cancer, and early death, according to the American Heart Association. There are a number of different factors that can affect VO2 max such as age, weight and even pregnancy, but as a general rule, the higher the number, the fitter you are.


An electrocardiograph machine shown at the UCSF Human Performance Center.

James Martin / CNET

The Apple Watch has been tracking its users’ estimated VO2 max for a few years now, but it took some digging to get there. First you might find it in the Health app on iPhone and most recently in the Trends tab in the Fitness app. But even if this number happened to you, Apple provided little context as to what it meant to you, plus it required you to complete a certain number of outdoor runs or brisk walks to populate.


A high cardio fitness score on the Health app.


With the latest news IOS 14.3 update, the Fitness app will now rank the maximum number of VO2 by reference to your fitness level: high, above average, below average or low. This is similar to what other trackers like Fitbit and Garmin offer on some of their devices, but the Apple Watch will also give you the option to be notified on the watch if your cardio fitness score drops in the low range.

You won’t even have to sweat to get your cardio fitness score. VO2 max on Apple Watch can be calculated as you move normally throughout the day and not necessarily during strenuous exercise, as long as it gets your heart racing. It’s also backward compatible, which means you’ll be able to see your score immediately after updating your watch if you’ve already received your VO2 max information on the app.


The low cardio alert on the Apple Watch.


Apple predicts that measuring and evaluating VO2 max can help motivate you to improve your fitness, in the same way that seeing your daily steps or calorie consumption on your watch can encourage you to move more.

“The ability to measure something for some people can be really motivating to see how it changes,” says Dr. Sumbul Desai, Apple’s vice president of health. “In this way, cardio can be a really useful measure for everyone, not necessarily just for those who run marathons.”

The more you know, the more you can improve

Measurement of VO2 Max required a laboratory test. Patients were put on a treadmill or stationary bike while connected to a heart rate monitor and a mask measured the oxygen exchange. Having this metric readily available on their wrist or phone without having to set foot in a doctor’s office can help users set measurable fitness goals over time.

“The really special thing about VO2 max is that you can actually do something about it. And the key to doing that is to practice more and increase your intensity, you will actually see improvement,” says Dr. Desai.

Adding a couple of extra steps a day won’t move the needle when it comes to cardio or VO2 max activity. Improving your cardio fitness level will require you to push yourself while exercising for a longer period of time, whatever that means to you. If you are fitter, this could be through high intensity interval training (also known as HIIT), but if you are just getting started it could be anything that increases your heart rate, such as taking a brisk walk.

Capturing VO2 max data on your wrist can be helpful in understanding your fitness levels, but as with any wearable, there are caveats. “It seems unlikely that accelerometers and PPG sensors alone [in the Apple Watch] it can capture all the nuances of medical testing and therefore shouldn’t be seen as a substitute, “says Dr. Geoff Tison, cardiologist and assistant professor of cardiology at the University of California at San Francisco.” But if it’s well validated and with low enough error, the ability to passively track these metrics in large numbers of people without complex equipment could be invaluable. “

CNET has not tested the VO2 max on the Apple Watch against the lab equivalent for accuracy and this metric should not be used for diagnostic purposes. As always, before starting an exercise program, consult a doctor or other qualified health care practitioner about any health-related health concerns or goals.

Now playing:
Watch this:

We tested the Apple Watch ECG on a hospital ECG


The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a doctor or other qualified health care practitioner with any questions about a medical condition or health goals.