The other day I woke up with a sore throat, which could have been a sign that I was getting a miserable summer cold. But as an optimist in denial, I wondered if perhaps it had to do with the fact that I slept with a fan blowing directly in my face for roughly eight hours. There is an old Korean belief that sleeping with a fan on will kill you, which is dramatic. But at the very least, could my fan be making me sick?
It's possible that sleeping with a fan could mildly dry out your throat, because when air gets moved around, it makes the air feel drier, says Philip Chen, MD, assistant professor and programme director in the department of otolaryngology at UT Health San Antonio. And if you're breathing in this extra-circulated air, then it could theoretically dry out your nasal passages and throat, although this is probably so minor that most people wouldn't notice the effects, he says. After all, "the mucus and anatomy of your body are also very efficient in humidifying the air you breathe," he says. But you may have also heard some people say that sleeping with a fan on is bad for allergies. Is there any truth to that?
Well, it's true that pollen, pet dander, dust, and allergens tend to settle on the ground or surfaces in your home, Dr. Chen says. Fans can "disturb" those particles, which could worsen allergy symptoms temporarily — but again, it's usually not a huge issue, he says. "Most of us do not have so much pollen in our homes that allergy symptoms are that severe, unless the window is open or we have a pet that we are allergic to," he says. Also, air-conditioners can blow allergens around the room, too, he says.
The good news is, there really aren't scientifically proven adverse effects of fans.
Philip Chen, MD, assistant professor and program director in the department of otolaryngology at UT Health San Antonio
If you do wake up feeling like you have a scratchy throat, the sniffles, or any other allergy symptoms, then it is most likely something else in your bedroom that's triggering it besides your fan, Dr. Chen says. "If the window is open, the fan is not the problem. If there's a pet in the room, then the fan is also not the problem," he says. Or it could mean that you are in fact getting sick.
So, ultimately your fan is not always the enemy. "The good news is, there really aren't scientifically proven adverse effects of fans," Dr. Chen says. If you find that your A-C or fan dries out the air to an uncomfortable degree, you can always get a humidifier. And remember: when A-C is not available, a fan is much better than nothing at all.