I mean physically. Like, knock back 6 pints of whatever in a relatively short space of time. I could drink some lager/stout/cider quickly - like possibly a 3rd of the glass if I'm thirsty, and then just sip the rest of it over a longer period of time. I wouldn't even be a fan of beer, but I'd be the same even with a drink I do like, served in the same format. I've heard about beer being more dehydrating and being easier to drink more of, but I've never really found that.
Do people just have to train themselves to do it? Do they force themselves through some pain barrier in order to become a pintman or pintwoman?