This came up at my running club, and a few posters in the Covid thread asked about it. As it’s an interesting subject and @chad and @Nate_Pearson have often touched on the subject I thought I’d spin up a thread.
This is a recent article:
And a paper published last year in the a journal of Sport and Health Science
EDIT - the graph that was here is disputed by the paper
The science on this subject does seem to be developing, so there may be a ways to go before achieving certainty.