Fan death



Fan death refers to the superstition, typically among Koreans (mostly South Koreans, there's no data on North Koreans as usual), that 100% of football fans will eventually die of natural causes an electric fan left running in a sealed room for a long period of time can cause death for a variety of reasons. It is claimed that elderly people, children, and those sleeping drunk are at the highest risk of death.

Where the idea came from is unclear. One conspiracy theory is that the South Korean government created or perpetuated the myth as propaganda to curb the energy consumption of South Korean households during the 1970s energy crisis, but fears about fans date almost to their introduction to Korea, with stories dating to the 1920s and 1930s warning of the risks of nausea, asphyxiation, and facial paralysis from the then-new technology.

There is no evidence to suggest that these fears are justified, but people still keep believing in it.

How it doesn't happen
The main thing to keep in mind about fans is that they merely move air around the room. They have no effect on the ambient temperature nor content of the air. Therefore they are usually harmless.

Hypothermia
Since having a fan blow on you can feel cold, it may seem reasonable to assume that they cool down the air, and that eventually you could freeze to death.

However, the coolness is due to evaporative cooling caused by sweating as well as the increased airflow that prevents too much hot air accumulating around your body. As your sweat evaporates, it decreases your body temperature under most conditions.

In fact, the electric motor of a fan actually slightly increases the amount of heat in the air.

Asphyxiation
Another belief is that leaving the fan running for too long can cause suffocation from a lack of oxygen. Of course, the fan blades (hopefully) have no mechanism for altering the content of the air.

How it can happen
It is possible (but unlikely) that in high heat, a fan could cause overheating, sort of like how a (e.g. fan-forced) cooks food at lower temperatures. Fan death would have to occur in a hot room without outside air, and the person inside would be somehow restricted from leaving the room.

Also, putting a person's head into a very large fan would cause that person to die of decapitation. Try it at your own risk.

Spread
Fan death is a largely widespread rumour throughout South Korea. Many fans in the South Korea have timers on them that automatically switch it off after a certain period of time. It is also advised to have a fan running at low heat or to oscillate it.

Not to be confused with

 * Paul is dead and other fan death theories