There is a widespread belief among some South Koreans that leaving a fan on in a closed room at night can cause death.
What could be more peaceful than a night of rest with a little fan gently blowing the air of your bedroom across your body? It sounds harmless -- unless, perhaps, you are from South Korea, where there is a widespread belief in "fan death," the mortal danger of sleeping in a closed room with an electric fan. Many fans in South Korea come equipped with timers so that they will not remain on throughout the night. The Korea Herald called the belief " one of Korea's best-known urban legends."
It's a big enough deal that Korean Consumer Protection Board put out an advisory in 2006:
If bodies are exposed to electric fans or air conditioners for too long, it causes bodies to lose water and hypothermia. If directly in contact with a fan, this could lead to death from increase of carbon dioxide saturation concentration and decrease of oxygen concentration. The risks are higher for the elderly and patients with respiratory problems.
From 2003~2005, a total of 20 cases were reported through the CISS involving asphyxiations caused by leaving electric fans and air conditioners on while sleeping. To prevent asphyxiation, timers should be set, wind direction should be rotated and doors should be left open.
According to Snopes, "There are other, more loony, theories about what causes fan death. One asserts the fan's blades chop up oxygen into carbon dioxide, rendering such mutilated air unbreathable."
No one seems to know why this belief persists, given that its position as a medical condition is dubious. There is some speculation that it has its origins in 1970s efforts by the South Korean government to curb energy use. The natural tendency is to write it off as some kind of crackpot belief.
While it seems likely that the reported cases of fan death have other causes, such as excessive drinking or undiagnosed heart conditions, the relationships between beliefs and physical health are tough to pin down. Alexis Madrigal wrote last year about the case of more than 100 Hmong immigrants killed, in a sense, by night spirits, or, if not by night spirits directly than "by their beliefs in the spirit world, even if the mechanism of their deaths was likely an obscure genetic cardiac arrhythmia that is prevalent in southeast Asia," he wrote. How beliefs shape biology, he concluded, is something "we don't understand ... quite as well as we'd like to think."
A University of California San Francisco medical sociologist who has studied the Hmong, argued for a "local" understanding of biology in her book on night spirits. "Since meaning has biological consequences, and meanings vary across cultures, biology can operate differently in different contexts," Shelly Adler wrote. "In other words, biology is 'local' -- the 'same' biological processes in different places have different 'effects' on people."
That is to say, if you believe hard enough that something might harm you, it actually might. That's the dark side to the placebo effect and squares with the emerging science of the very real mind-body connection.
Regardless of whether Fan Death is "real" -- a belief with real effects -- or a total mirage, it can become an easy tool with which to mock Koreans. As "The Korean" (as the anonymous blogger refers to himself) writes on Ask a Korean:
Fan Death has been the favorite topic of anyone who wished to ridicule Korea. Belief in Fan Death is supposed to show that Koreans lack "critical thinking". There is a whole website devoted to it: www.fandeath.net. The Wikipedia page describing Fan Death is, reading between the lines, dripping with contempt. Even a good-natured Korean blog like Stuff Korean Moms Like uses the Fan Death picture to describe the strangeness of Koreans. Similarly, requests at Mythbusters(best show EVER) asking to debunk Fan Death are interspersed with
such bile as: "Do you seriously expect anyone to do a TV program to determine whether untold generations of inbreeding on the Korean Peninsula resulted in a bizarrely maladaptive genetic defect that would cause the carrier to die from a slight breeze on their face and this defect finally manifested itself only after the invention of the Electric Fan?"="#3281966689">
And, of course, no country or culture is unique in holding unfounded beliefs. Perhaps the best analog closer to home is the persistent belief that swimming after eating can cause drowning (and for many more examples see "List of Common Misconceptions"). If another culture's strike us as totally unfounded, let it serve only as a reminder that though the ghosts we believe in may be different, they are ghosts just the same.