Fan Death

fan death

Fan death is a putative phenomenon, generally accepted only in South Korea, in which an electric fan left running overnight in a closed room can cause the death of those inside. Fans sold in Korea are equipped with a timer switch that turns them off after a set number of minutes, which users are frequently urged to set when going to sleep with a fan on.

The genesis of this misconception is unclear. Some have speculated that the South Korean government created the idea of fan death as propaganda in order to curb the energy consumption of Korean households. This theory is based on the fact that reports of fan death first appeared in the 1970s. This coincided with the 1970s energy crisis, which led to a short supply and high prices of oil; it also coincided with the rule of President Park Chung-hee, who listed attaining a self-reliant economy and modernization as his top goals, as announced in his Five Year Economic development Plan.

Electric fans sold in Korea are equipped with a “timer knob” switch, which turns them off after a set number of minutes. This is perceived as a life-saving function, particularly essential for bed-time use. There are several purported explanations for the precise mechanism which might result in death. The most common explanation is that fans cause hypothermia. Hypothermia is abnormally low body temperature caused by inadequate thermoregulation in humans. As the metabolism slows down at night, one becomes more sensitive to temperature, and thus supposedly more prone to hypothermia.

People who believe in this theory think that a fan operating in a closed room all night will lower the temperature of the room to the point of causing hypothermia. However, fans do not cause the room temperature to drop, they lower body temperature by increasing the convection around a person’s body so that heat flows into the air more easily, and by the latent heat of vaporization as perspiration evaporates from the body. However, there is no scientific study which indicates that this effect would be sufficient to cause hypothermia unless the temperature were already very low.

Another common rationale is that fans cause asphyxiation. It is alleged that fans may cause asphyxiation in humans due to oxygen displacement and carbon dioxide intoxication. In the process of human respiration, inhaled fresh air is exhaled with a lower concentration of oxygen, and higher concentration of carbon dioxide, causing a gradual reduction of O2 and buildup of CO2 in a completely unventilated room. Other indoor sources of carbon dioxide include burning fossil fuels, such as a gas-fueled water heater, and seepage through foundations in areas of high CO2 soil content.

Carbon dioxide is a colorless, odorless gas, and because it weighs 1.5 times more than normal air, it tends to concentrate toward the floor, depending on temperature and air currents. In South Korea, some people sleep on traditional floor mats called yos, while others prefer western-style beds, and floor vents may be absent in rooms equipped with radiant underfloor heating, called ondol. Asphyxiation is an unlikely cause of fan death because few rooms are totally sealed, and the fan would tend to keep CO2 and other gases well mixed.

It should be noted, however that the US EPA does discourage people from using fans in closed rooms without ventilation during excessive heat, specifically when the heat index is above 99 °F (37 °C). Although the increased air movement will increase evaporation of sweat, this increases the heat stress placed on the body and can speed the onset of heat exhaustion and other detrimental conditions.

In the summer months mainstream Korean news sources regularly report on alleged cases of fan death. A typical example is this excerpt from a 2011 edition of ‘The Korea Herald,’ an English-language newspaper: ‘A man reportedly died on Monday morning after sleeping with an electric fan running. The 59 years-old victim, only known by his surname Min, was found dead with the fan fixed directly at him.’ However, this article at least nominally repudiates the fan death myth, saying that there is ‘no evidence’ for it.

Gord Giesbrecht, a professor of thermophysiology at the University of Manitoba, is a leading expert on hypothermia: ‘It’s hard to imagine death by fan, because to die of hypothermia, one’s body temperature would have to get down to 28 [°C], drop by 10 degrees [Celsius] overnight. We’ve got people lying in snowbanks overnight here in Winnipeg and they survive. Maybe if someone was elderly and they were sitting there for three days in a sealed room with an electric fan turned on. Someone is not going to die from hypothermia because their body temperature drops two or three degrees overnight; it would have to drop eight to ten degrees.’ In addition, ‘the only way to verify whether someone had really died of hypothermia during the night would be to take a core body temperature the following morning. Waiting three days while the body was in the morgue wouldn’t work because the corpse’s temperature can drop during that time.’

One Comment to “Fan Death”

  1. hmm interesting

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