So if you are using sleep HRV as an indicator of recovery there may be some issues. In my case a longer or better night’s sleep is correlated with lower HRV (SDNN). That suggests there is something going on that isn’t about recovery at all (and higher SDNN is only associated with parasympathetic predominance and may be open to all sorts if intervening factors). I have collected a lot of data.
Poor sleep itself is associated in my case with high day stress which does make sense.
I don’t think sleeping less or worse can be causally related with worse recovery in any sane world. High day stress may of course drive a night-time shift in HRV, which might be a thing.




