Cardio Capacity (VO2 Max)

Cardio Capacity is one of Oura's Heart Health measurements, designed with an eye toward your future health and longevity. The Cardio Capacity feature is available for:

Gen3 and Oura Ring 4 with active membership
iOS
Android

This feature is not available on Gen2 or older.

What Is Cardio Capacity?
What Is VO2 Max?
How to Use Cardio Capacity
Walking Test
Manually Added Data
Future Me
Things to Keep in Mind
More Information

What Is Cardio Capacity?

Cardio Capacity is an age-adjusted estimate of your VO2 max reading, which is the maximum amount of oxygen your body is able to utilize during exercise. Cardio Capacity is a great measure of cardiorespiratory (aerobic) fitness because it signals how well your heart, blood vessels, and muscles work together.

What Is VO2 Max?

VO2 max, or maximal oxygen uptake, measures the maximum amount of oxygen an individual can utilize during intense, exhaustive exercise. VO2 max is generally measured in milliliters of oxygen used in one minute per kilogram of body weight (ml/kg/min). The greater your body's ability to supply oxygen to your muscles during sustained physical activity, the higher your VO2 max reading will be.

VO2 max varies significantly among individuals according to many influences, including age, sex, fitness level, and genetics. While it is commonly regarded as an athletic performance indicator, VO2 max correlates well with longevity, and is therefore a useful metric for anyone interested in their health, not just athletes.

How to Use Cardio Capacity

You can locate Cardio Capacity in the My Health tab. The initial reading will show a number based on anthropometric data (age, sex, height, and weight) as entered in My profile under the Oura App menu. This number is an estimate only, based on population averages.

Depending on your VO2 max number, your Cardio Capacity will fall into one of four levels:

Peak: very high within your age group
High: high within your age group
Fair: average or slightly below average within your age group
Low: below average within your age group

For a more precise measurement of your Cardio Capacity, the Oura App will prompt you to complete a six-minute walking test. You can also manually add a VO2 max value if you have a lab test result or a VO2 max reading from a trusted source, such as another wearable.

Walking Test

Tap Take the walking test to start.

Location services must be turned on for the app to measure your Cardio Capacity
Make sure your phone is charged above 20% before taking the walking test and carry your phone with you for the entire route
Walk at a brisk pace (as quickly as you can without running out of breath)
Choose a straight, level route that avoids traffic lights, which may interrupt a steady walking pace
Choose a route that avoids tunnels, which may interrupt GPS signal

During the walking test, Oura will use the distance traveled and your heart rate to calculate your Cardio Capacity. Please note that because Oura uses the physical distance traveled to calculate your Cardio Capacity, the walking test cannot be performed on a treadmill.

After completion of a walking test, the app will display a graph of any current and past measured Cardio Capacity. To better track your Cardio Capacity, we recommend that you take a walking test approximately once a month.

Manually Added Data

If you want to update your VO2 max with a value from an external source, select Add your current VO2 max to manually add a data point. Enter a number 1-100 and then select Done.

Any VO2 max data can be deleted by swiping left on the entry and selecting Delete.

Future Me

Cardio Capacity naturally declines as you age. This decline can be mitigated with regular movement and exercise. The Future Me chart provides a visual representation of how your potential future Cardio Capacity compares to expected average decline.

The dotted blue line represents how maintaining or increasing activity levels can improve your Cardio Capacity. The solid white line is a prediction of your Cardio Capacity based on your current activity levels and expected population-level decline.

Both lines estimate how difficult or easy it would feel to climb several flights of stairs at different ages.

Things to Keep in Mind

The Oura walking test is not as accurate as a lab test, but is an easy and accessible way to understand your Cardio Capacity. The walking test may not give a precise estimation for high-performing athletes
Performing the walking test at high altitude may have an impact on your Cardio Capacity results
You may see gaps in your Cardio Capacity graph if you haven’t performed the walking test regularly. We recommend that you take a walking test approximately once a month
Although Cardio Capacity and Cardiovascular Age are both part of Oura's Heart Health feature, the two measurements do not have a direct impact on each other. Seeing an increase or decrease in one metric will not necessarily mean seeing an increase or decrease in the other

The Oura Ring is not a medical device and is not intended to diagnose, treat, cure, monitor, or prevent medical conditions or illnesses. Please do not make any changes to your medication, nutrition, or workouts without first consulting your doctor or another medical professional.