My dad always claimed that having AC blasting right into your face (like in a car, with the vents pointing at you) could cause a stroke.
Somehow.
Yeah, right.
I love straightforward arguments like this. If something so extremely common was any non-trivial risk the number of incidents would stand out. As it is influenza and a bunch of other similar things that are well known to cause pneumonia dominate the stats. Anything caused by AC would be down in the noise, if it exists at all.
Take falling off ladders. Seems like a rare enough occurrence. Yet the people who track such things can confidently state that each year there are about 164,000 emergency room-treated injuries and 300 deaths in the U.S caused by falling off ladders. And given that many, many, more people use ACs than ladders far, far more often, the risks have to be awfully low to not catch the attention of people who track these.
Am I correct though, in that lack of good sleep for a few days will keep your immune system from fighting properly?