Instead of measuring how fast or far a user went during a run or bike ride, or metrics like calories burned, Cardio Effort measures how hard their cardiovascular system was working during exercise and how long that effort was sustained. Cardio Effort is calculated for individual workouts taking into account both intensity and duration but provides a plain language evaluation that compares a user’s cumulative weekly effort against a personalized baseline.

One one end of the scale is a Light rating that’s described as being a “substantially lower cardiovascular strain than your usual baseline.” The rating scale progresses through Fair, Maintaining, Building, and Reaching at the other end which means your weekly Cardio Effort had a “markedly higher exposure relative to your baseline, signaling that it may be time to prioritize recovery.” So instead of always pushing a user to increase their efforts, the feature does make recommendations for rest when it may be more beneficial.

Oura Rings already support VO2 Max readings that are used to track aerobic capacity, but the previous Cardio Capacity feature was somewhat cumbersome because estimating a user’s maximum oxygen uptake required a six-minute walking test for calibration. The new version, automatic VO2 Max, currently available as a beta feature through Oura Labs, automatically activates after users complete five “qualifying GPS-enabled activities” that include walks, runs, and hikes.

Once activated VO2 Max readings will be available in the Oura app’s My Health Heart Hub section with a user’s current estimate, their capacity rated as low, fair, high, or peak, how their aerobic capacity has changed over time, and personalized insights for when VO2 Max “meaningfully shifts or stays consistent.”