> I don’t think circadian rhythms should have been mentioned in the title of the article at all. It should be about travel which is more broad and accurate to w

> I don’t think circadian rhythms should have been mentioned in the title of the article at all. It should be about travel which is more broad and accurate to what they were measuring. Take this study as one study in a large body of research (and apart from scientific interest there is great financial interest as well). From that you can derive some priors on what will be likely mechanisms of effect and effect sizes. What do you think is the primary effect behind travel? Sure there is discomfort, noise, stress, unfamiliarity of surroundings etc., but the primary effect is the disruption of circadian rhythm. And again there are a number of mitigation strategies such as taking melatonin, controlling stimulants (light in particular), sleep coaching etc, but even if you do all of this well (I know from others sports that this is done routinely at the elite level), your body is still at a different point in the circadian rhythm. > The opposing crowd and lack of familiarity with the stadium come to mind. You are absolutely correct. I don't think the paper excludes that other factors can confound results. I'm sure other studies will have tried to quantify these factors and there will be priors for that.