sweating it out

While waiitng in front of the library to go online the other day, one of the men also waiitng (a coach apaprently) was telling his friend that one of his tudents came to practice and told him his bronchitis was acting up.
He told the guy (17 years old) to go home, take a shot of whiskey, bathe, then lie down in a warm bed to “sweat it out”.
I’ve heard of this before; not for bronchitis though.
Does it work?
How?
How can you sweat a sickness out?

Oh gosh. I seem to have the sickness called misspelling words…
that would be student and also waiting…sigh…