No, from europe, Swiss. There's something you learn here as children, not to sleep with wet hair. Same reason, uncontrolled (from your body) cooling in a state where your body has limited capabilities to counter it, limiting your immune system. I'm due to circumstances a bit more prone, i'd get a sore throat if i'm not covered, but that doesn't mean it's good for you.

Edit: right, tropical climate, forget it.