> Similarly, in a heated room without an outside source of airflow, very hot air is constantly pushed directly to your body, which is a far more effective way of raising your body temperature rather than “baking” in hot air. If you get enough of this, you would die – of hyperthermia, or abnormally high body temperature
For the air to actually heat your body enough to kill you, you need:
* Room temperature that is high enough to kill you (>43 degrees celcius). Any temperature below this -- and the fan helps avoid hyperthermia by averaging out the body temperature with the environment.
* You have to be fully dehydrated, otherwise even air hotter than your body will cool you up.
* According to http://www.currentresults.com/Weather-Extremes/hottest-citie... you won't find any place in the world where the night time temperature is well above 30 degrees, so Fan Death is a total myth.
* According to http://www.mherrera.org/temp.htm no place in Korea ever exceeded 40.3 celsius degrees between 2002 and 2012. So if you slept with a fan, during the hottest day of the hottest city in Korea, you'd still not be hot enough to be killed.
If you sleep on on extremely hot days (not nights), with (>43C) a fan directly aimed at you may increase the risk of hyperthermia (which exists anyway). However, on any day with more than 36 degrees Celsius, you are unlikely to leave a fan directed at you, because it will feel warmer than without the fan.
In short, it is a silly urban legend, more likely to cause hyperthermia in people who are afraid to use fans to lower their temperatures during the night.
