Unaligned HRV Values?

Hi everyone. I use an Oura ring 4, eight sleep, and Ultrahuman Air, and I consistently get huge differences in HRV from the Air to the Oura/eightsleep (the Oura ring and eightsleep agree with each other within a few percent)

Has anyone else seen the air giving low HRV’s?

Looking at days with both low and high HRV, the Air is always lower by a ~20% margin or more

Low HRV night: Ultrahuman air: 35 Oura ring: 42

Delta: Oura is 20% higher

High HRV night: Ultrahuman air: 64 Oura ring: 80

Delta: Oura is 25% higher

The delta is consistently about 20-25% across the last 20 days (I’ve only had the Air for about 3 weeks)

The long term delta in the data is finally made pretty obvious in the cardiovascular ages estimated by the Oura Ring and Ultrahuman Air disagreeing:

Age predictions: Oura Ring 4 age: 24 Ultrahuman Air age: 31

7 year difference! 👴

Would love to hear from others using multiple rings~