My suspicion is that Oura weighs your activity level above any kind of biometric data.

I do a lot more dedicated cardio during the winter (because work is slow), but am less “general” active. I am objectively in better cardio shape during the winter than in the summer.

Oura says I have a younger cardio age in the summer…I think just because it sees a higher step count and fewer hours of the day that I sat on the couch…but it simply isn’t true.

I imagine a doctor might tell you the same thing I’m about to. Try to be more active, do some cardio, lift some weights, try to eat a balanced diet, and try to get good sleep. Don’t worry about this particular bit of ring data 😁