Deliberate cold exposure can sharply increase adrenaline and dopamine, potentially accelerating hangover recovery.

“There is some evidence that increasing levels of epinephrine in the bloodstream can actually help with alcohol clearance. That was very surprising to me, and I want to point out this is not a large and robust literature, but there's some evidence pointing to the fact that when levels of epinephrine, adrenaline, are raised in the brain and bloodstream, that some of the components of alcohol metabolism can be accelerated and some of the inebriating effects of alcohol can be reduced, so maybe this old school lore of taking a cold shower actually has something to it.”