HRV: Oura vs Polar

I was using a few wearables to measure my HRV - and it seems that the data across different wearables are inconsistent.

Here’s the summary on the comparison between Oura and Polar (i was using an Oura ring 3, vs a Polar Unite) (and yes those two are different price points)

  1. Polar HRV is consistently higher than Oura and Polar’s HRV readings are more volatile than Oura’s in general.

  2. Both wearables record spikes in HRV data, up to a 30ms jump in HRV in Polar’s case which is a huge change.

  3. Not much consistency between Polar and Oura’s measurements to compare HRV trends, unlike for heart rate.

  4. The differences in HRV between Polar and Oura could be because Oura takes readings from your finger while Polar uses your wrist, especially for a metric as sensitive as HRV.

I wrote a full guide with the data and graphs here


Hello, Polar seems to provide weird results in your case. I dont thinks that’s because of place of measure - finger vs wrist shouldnt differ that much.

Here is my data for last 3 months - Oura 2 VS Fitbit Charge 5 (wrist).

It’s easy to see that i have pretty similar trends on wrist and finger, but fitbit (red) seems to have systemically lower values compared to oura.

T-test confirmed data normality for both oura and fitbit data, so i can just go with pearsons correlation:

Pearson’s correl r=0.93 which is pretty high and confidence interval is pretty narrow [0.9,0.95] which means both devices works pretty similar.

So i’m not sure what Polar did measure in your case.

Thanks for sharing - agreed, I think the data should be the same, but polar measures consistently different results