running is the best cure foa hangover,I find. Drink a couple of pints of water beforehand, and it gets sweated out, and it feels like it's taking all the toxins with it. I've got rid of minging hangovers by midday thru running.
I rekon that it takes three days of drinking water to properly hydrate your joints, and three days of not drinking water to unhydrate, and although binge drinking will accelerate the dehydration, shouldn't be enough to dehydrate you overnight.
However, contrary to what has been said above, I think that running dehydrated could cause injury.