How Is Cardio Fitness (VO2 Max) Calculated in Athlytic?

Athlytic calculates Cardio Fitness based on estimated VO2 Max, a widely recognized metric for measuring cardiovascular endurance and aerobic capacity. Unlike Apple’s method, which limits Cardio Fitness calculations to running, walking, and hiking, Athlytic provides estimates for all workout types, offering a broader picture of your fitness across various activities.

Apple doesn’t disclose exactly how they calculate Cardio Fitness, but based on the available data from the Apple Watch (heart rate, location, and speed), it’s likely that their formula is similar to the widely used VO2 Max estimation method. This is why Apple only calculates Cardio Fitness for running, walking, and hiking workouts, as those activities provide consistent heart rate and movement data needed for their estimation.

How Is Cardio Fitness Estimated in Athlytic?

Athlytic calculates Cardio Fitness using the following formula:

Where:

•HRmax = Maximum Heart Rate

•HRrest = Resting Heart Rate

This formula provides an estimated VO2 Max value, similar to how Apple calculates Cardio Fitness, though Apple does not disclose its exact methodology.

Why Is It an Estimate?

A true VO2 Max test requires a cardiopulmonary exercise test (CPET), where an individual runs or cycles at increasing intensities while wearing a mask that measures oxygen intake and CO2 output. Since this isn’t practical for everyday users, Athlytic (and Apple) use heart rate data as a proxy for estimating VO2 Max.

If none of these troubleshooting steps resolve the issue, consider reaching out to Athlytic support for further assistance.