It’s not just superstition. Air conditioned air can be bad for you if you’re not maintaining it. It is also drying so it can bother your throat, eyes, and skin. It might make it easier to transmit COVID though that might just be in door air. I definitely prefer comfortable outdoor air to air conditioned air.
No I think that there's more to it than superstition - We often blame things on superstition when we don't understand them ourselves.
I've been playing around with sleeping with a fan & air-conditioning and I always notice that my throat is all dryed out in the morning from the air flow directly over my face.
I need a couple of glasses of water to re-hydrate after sleeping with a fan or air-conditioner, so if its not too warm a night I prefer to leave them off. I seem to get a better night's sleep too, but maybe that's just because it's a cooler night.
