Cardio Fitness levels feature on Apple Watch, here’s what you


Cardio fitness levels Apple Watch
Apple Watch and Apple Health app cardio fitness levels

Apple’s Health app offers a feature called Cardio Fitness levels. Although this looks like a new feature, it’s actually rebranding the older VO2 max. Apple renamed VO2 max to Cardio Fitness–to make it more user-friendly!

We really like this rebrand because the Cardio Fitness feature lets users know via notifications if they are trending with low cardio fitness levels.

Related reading:

Why your cardio fitness matters

With this update, Apple is leveraging VO2 max scores to show a user’s cardio fitness levels.

Cardio fitness is a strong indicator of your physical health. You maintain or improve your cardio fitness with physical activity.

And conversely, a decrease in physical activity also corresponds to a lowering of your overall cardio fitness level.

What factors determine your cardio fitness?

Many factors determine your cardio fitness levels. The primary determinants are age, sex, lung conditions, and heart conditions (resting heart rates.

VO2 max is the gold standard for establishing and personalizing each person’s cardio fitness level.

VO2 Max stands for V (volume)  + O2 (oxygen)  + Max (maximum). It measures the maximum amount of oxygen your body can use while exercising or engaging in physical and aerobic activity.

The Apple Watch leverages the VO2 max standard to determine and assign a score for your cardio fitness level.

What is a good score for Apple’s cardio fitness level (VO2 Max)? Cardio fitness above average from Apple Watch and in iPhone Apple Health app

Apple Watch leverages the VO2 max score to determine each person’s Cardio Fitness level value. Apple bases your cardio fitness score based only on these exercises: Outdoor Walks, Outdoor Runs, or Hiking workouts in the Apple Watch Workout app.

Your cardio fitness level measures how hard your heart and the score itself depends on your age, gender, weight, height, and any medication you take that could impact your heart. This feature is available for anyone 20 years or older.

According to Apple, for men ages 30-39, an average score should be above 43, while for women of that same age, it should be above 30.

Generally, varying VO2 max scores indicate (depending on age and gender)

  • Scores between 15 (60 years old+) – 29 (under 30) signify a low cardio fitness level. 
  • A score between 25 (60+) – 53 (under 30) is considered average to above-average cardio fitness.
  • Anything between 32 (60+) – 54 (under 30) qualifies as a high cardio fitness level.

However, this dramatically varies with a person’s age and gender.

For example, a female above 60 years old is considered low at 15, above average at 20, and high at anything above 25!Good Cardio Fitness level score on Apple Watch

Good Cardio Fitness level score on Apple Watch

So it’s crucial to review the cardio fitness levels for your current gender and age before checking your current cardio fitness level.

The philosophy behind this change is apparent from Apple’s guidance:

In a 2016 scientific statement, the American Heart Association recognized a growing link between low cardio fitness and a higher risk of significant health issues, such as heart disease, high blood pressure, and obesity, later in life. Research even suggests cardio fitness is a stronger predictor of mortality risk than common risk factors like smoking, diabetes, and hypertension.

“Cardio fitness is increasingly recognized as a powerful predictor of overall health, and we are making it even more accessible to more people,” said Jeff Williams, Apple’s chief operating officer. “Using its advanced sensors, Apple Watch now brings estimation of low cardio fitness levels from clinics directly to a user’s wrist, so people have more insight into how they can improve their long-term health through daily activity.”

If Apple determines that your cardio fitness levels are low for your age and gender, you receive a low cardio fitness notification on your watch and from the Health app. Apple Watch low cardio notificationApple Watch low cardio notification


When your cardio fitness levels remain low, you get additional notifications until the Health app detects an increase into average or better levels.

How to enable or disable Cardio Fitness Level notifications on your Apple Watch

The cardio fitness level notifications are easy to enable or disable using the Watch app on your iPhone.

  • Open the Watch app on your iPhone.
  • Tap on ‘My Watch’ at the bottom.
  • Next, tap on Notifications and scroll down and select ‘Heart.’
  • Find ‘Cardio Fitness Notifications’ here.Enable or Disable Cardio fitness level notificationsEnable or Disable Cardio fitness level notifications
  • Toggle the setting on to enable or off to disable these notifications.

Per Apple, if your cardio fitness level stays low for an extended period (months, not days), you receive a notification every four months.

Since the calculation of Cardio fitness level depends on your resting heart rate (RHR), Apple recommends you wear your watch when you sleep to get an accurate score.

Typically individuals with higher VO2 Max have lower heart rates while running at the same pace as individuals with lower VO2 Max.

See these articles to troubleshoot problems with cardio fitness data on your Apple Watch:

Why does Apple call it cardio fitness instead of VO2 Max?

The VO2 max health metric isn’t well-known, and for most people, there was a lot of confusion around it. Indeed, most people ignored it because they didn’t understand it!

Hence, Apple rebranded it as an overall Cardio Fitness Level score on the Apple Watch and the Health app.

And most of us know what both cardio and fitness mean–and can easily translate it into our heart’s health.

Cardio Fitness Level on FitbitCardio Fitness Level on FitbitFitbit app Cardio Fitness level score

Apple is not the first when it comes to using this term.

Fitbit also uses a Cardio fitness score via the Fitbit app and calculates it using the VO2 max metric.

How does Apple Watch determine low or high Cardio Fitness score?

Apple uses the established FRIEND database to look up reference values by sex and age and compares it with the readings collected from your Apple Watch to determine low or high Cardio Fitness score.

The Fitness Registry and Importance of exercise national database (FRIEND)  is a repository that holds reference values for VO2 Max / Cardio Fitness scores. 

These are the first cardiorespiratory fitness reference data using measures obtained from CPX (cardiopulmonary exercise testing), the gold standard for VO2 Max, in the United States. 

FRIEND can be used to provide a more accurate interpretation of measured VO 2max from maximal exercise tests for the US population compared with previous standards on the basis of workload-derived estimations.

What causes Inaccurate Cardio Fitness score readings on Apple Watch?

Having said that, there are some factors that influence the accuracy of cardio fitness score and these have been highlighted by Apple in its research paper. We highlight the most important ones for you below:

  1. The user has not updated personal details on the Apple Health app. If you enter an incorrect age, sex or weight, you may consistently see inaccurate VO2 max estimates.
  2. Pregnancy can cause inaccurate estimates for VO2 max
  3. Cardio Fitness scores will be low as per Apple, if sensor data is recorded during behaviors that increase user’s work load in a way that Apple Watch can’t detect.
      • Apple Watch may show you inaccurate reading if you are running or walking on sand or any surface that increases your effort.
      • You are running with a backpack carrying extra load
      • Factors that increase heart rate, such as dehydration, caffeine intake, extreme heat, or recent transition to high altitudes may also lead to underestimates.

The 5.75 Minutes mystery for Apple Watch Cardio Fitness score

Although Apple’s guidance says three minutes of activity, their research also shows that the optimal number of exercise minutes to generate a VO2 max or Cardio Fitness score is 5.75 minutes.

93% Percentage of participants who completed at least 10 outdoor pedestrian workouts longer than 5.75 minutes and received at least one estimate in their first 10 workouts

79% of outdoor pedestrian workouts longer than 5.75 minutes received an estimate.

Bottomline, if you just purchased an Apple Watch, you may have to workout for at least 10 regular outdoor runs/walks/hikes in order to increase the chances of seeing your accurate VO2 max score.

How do you improve your Cardio fitness level score?

Exercise and healthy weight loss are two ways to improve your Cardio fitness level score. 

  • Weight loss lowers your body fat percentage and helps with improving your cardio fitness levels.
  • Increased exercise helps you improve your cardio fitness score by up to 20 percent over two to three months (source: Kennedy, Phys. of Sport and Exer.). 

How much exercise do I need to get an average cardio fitness score?

Recent results from Apple’s Heart and Movement Study (in collaboration with Brigham and Women’s Hospital and American Heart Association) indicate that how much activity you engage in each week really matters. 

Across genders and ages, participants with above-average Cardio Fitness levels averaged more than 200 minutes of activity per week, while those with high Cardio Fitness averaged more than 300 minutes of activity per week

To improve overall cardiovascular health, the American Heart Association recommends at least 150 minutes per week of moderate exercise or 75 minutes per week of vigorous exercise (or a combination of moderate and vigorous activity.)

Tip: Add high-intensity interval exercises!

Incorporating high-intensity intervals in your workouts is an effective way to see a noticeable improvement. But don’t forget to also do your outdoor walks, hikes, or runs to get Apple to measure your cardio fitness.

Interval training includes any workout that alternates between intense bursts of activity followed by a lower-intensity activity or rest periods.

This type of episodic interval training has proven to be one of the best levers to increase your VO2 max and, therefore, your cardio fitness level.

Apple Fitness+ Workout Modes

Apple Fitness+ Workout Modes

This is where Apple Fitness+ comes in handy!

Apple’s Fitness+ subscription offers several trainer-led classes that focus not only on High-intensity interval training.

But these workouts also guide users through activities that improve their Cardio Fitness levels.

Plus, all classes offer modifications so people of any fitness level can join in!

Apple's Fitness Plus new BURN BAR

Apple's Fitness Plus new BURN BAR

As a Fitness+ student, Apple’s unique Burn bar is another excellent feature to leverage.

The Burn Bar shows how your current workout intensity and effort stack up against anyone who previously did that same workout.

This Burn Bar helps you push through your workout to get the most out of high-intensity fitness training classes for people who love a little competition.


Understanding your cardio fitness level helps you know more about yourself and take ownership of your body and exercise routines.

How do you stay fit today and access your overall cardio performance?

What features on the Apple Watch help you assess your overall fitness levels?

Please let us know using the comments below.


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