K_A's Avatar

I have that problem, too. I think it's the large temperature differential between the spot where the AC is blowing on you and everywhere else; it confuses your body's temperature regulation system and makes you feel sick. I always run the AC on defrost so that it spreads out when it hits the windshield and hits my body pretty evenly.

I just turn the little hole thingies and it hits my body. I love being cold.

I figured it was just the vent system in general: the air in some cars just gives me get a headache or I become nauseous.

Yeah, that's what I figured for myself, too. Though if I have to be in a car with the AC on, I make sure no vents are pointed directly at me. If it gets too bad for myself, I'll end up cracking my window to get some fresh air.

Whenever possible I prefer all the windows to be rolled down.