Will sleeping in a closed room with an electric fan cause death?

Dear Cecil: Here in Korea there seems to be some kind of firmly established urban legend that sleeping with a fan on in a closed room during summer causes death, ostensibly by asphyxiation. Every summer the local press claims more than a dozen deaths. I enclose a snippet from a local E-mail chat group for your perusal. You can see just how far things have gotten. We’re relying on you to clear it up for us, I think this is outta our league. Muckaluk, via the Internet

Cecil replies:

Damnedest thing I’ve come across in … oh, probably two weeks. But whereas the Mountain Dew/shrinking testicles rumor was confined largely to teenage boys, this death-by-electric-fan story seems to be a common belief in Korea, even among knowledgeable medical people. If this is an indication of the national impressionability quotient, I could make a fortune selling these guys laundry balls.

Here’s an excerpt from the July 28, 1997, edition of the Korea Herald, an English-language newspaper:

The heat wave which has encompassed Korea for about a week, has generated various heat-related accidents and deaths. At least 10 people died from the effects of electric fans which can remove oxygen from the air and lower body temperatures. … On Friday in eastern Seoul, a 16-year-old girl died from suffocation after she fell asleep in her room with an electric fan in motion. The death toll from fan-related incidents reached 10 during the past week. Medical experts say that this type of death occurs when one is exposed to electric fan breezes for long hours in a sealed area. Excessive exposure to such a condition lowers one’s temperature and hampers blood circulation. And it eventually leads to the paralysis of heart and lungs, says a medical expert. To prevent such an accident, one should keep the windows open and not expose oneself directly to fan air, he advised.

One hears several theories on how fans do their deadly work: Hypothermia, i.e., lowered body temperature. Seems unlikely. Given the reportedly high humidity, a fan would just be blowing warm air around. However, various daredevils who have tried this and lived report that your face and throat can get pretty dehydrated. The flow of air over the face somehow produces a vacuum or other anomalous condition in front of the mouth and you suffocate. Gimme a break. Carbon dioxide builds up in the sealed room and, being denser than the other gases in air, sinks to floor level and suffocates you. Also unlikely — few rooms are totally sealed, and the fan would tend to keep CO2 and other gases well mixed. Heat stroke (fan irrelevant). Maybe, but the temperature was only in the 30s Celsius (more than 86 degrees Fahrenheit). Also, heat stroke typically affects older people with existing health problems, not teenage girls.

Told that “fan deaths” are unknown outside Korea, some locals claim Koreans are uniquely vulnerable due to a peculiarity either of their own physiology or of Korean fans. No argument here. Anybody who’d believe something like this definitely qualifies as peculiar.

So what do fan-death cases really die from? We consulted with Lieutenant Colonel Dave Hause, a deputy medical examiner with the U.S. Army Medical Corps. (Colonel Hause speaks for himself, by the way, not the Defense Department.) He writes:

If I had a 16-year-old die in a room at 86 degrees Fahrenheit in the presence of an electric fan, I’d strongly suggest an electrical check on the fan [possible electrocution]. Then I would be sure my toxicology studies were thorough [to check for poisons and drugs], that I had extensive microscopic examination [to check for disease], that the heart and brain were further examined by specialists [for abnormalities], and that assorted microbiologic studies had been done. If all these came out negative, I’d ask the investigative service to go back through the history again, on the assumption that the ‘suffocation’ was assisted. Of course, if the room was sealed well enough and the fan drew enough power, I suppose it could heat the room enough to kill. But then there ought to be an elevated core [body] temperature to support the diagnosis of heat stroke, not suffocation.

So nice to hear from a guy who knows what he’s doing. Maybe someday Koreans will get the same chance.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.