Another possible link is mood (as in mood disorders). Alcohol can improve your mood (temporarily). Exercise can improve your mood too. Perhaps there are peopl

Another possible link is mood (as in mood disorders). Alcohol can improve your mood (temporarily). Exercise can improve your mood too. Perhaps there are people whose mood is not so great, who seek ways to improve it, and who wind up discovering both exercise and alcohol work for that. Whereas people whose mood is already fine are less motivated to go searching for that sort of thing. (The article got close to mentioning this: "linked both exercise and drinking behavior to higher levels of sensation-seeking". But it doesn't seem like quite the same thing to me. A sensation is a short-lived experience, and mood is more of a mental state that persists for a while.)