Debunking the Science | The Dangers of Ventilators

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Because when it’s very hot, the wind can give a false impression of coolness without lowering the core body temperature.

“Beyond 36 degrees, fans don’t help cool body temperature,” says Glen Kenny, a University of Ottawa physiologist who published a study on this issue in May in the journal Lancet Planetary Health. “There is bad information circulating about this, it needs to be corrected.”

From 36℃, there is not enough difference between body temperature and air temperature for a draft to make a difference. “But there can be a false sense of coolness that leads to too much physical activity. This is particularly problematic for older people,” says the expert.

If the skin temperature is slightly lowered by blowing a fan when the air temperature exceeds 36℃, it will not affect the body’s core temperature (core temperature). However, it is the core temperature of the body that is associated with the negative effects of heat on health.

2021 Heat Dome

Mr. Kenny did his study, which modeled more than 100,000 human temperature regulation patterns, because he was “irritated” by the unanimous recommendations of public health authorities around the world.

“The World Health Organization has recommended fans at all times during heat waves, Lancet also. After 619 people died in two weeks during a heat wave in 2021, the BC coroner suggested fans be distributed to people during such events. But often, during these times, temperatures exceed 36℃ and fans are more dangerous than beneficial.

When the difference between the body’s core temperature – normally 37.2℃, but can reach 40℃ during heat stroke – and that of the ambient air is large enough, wind can increase sweating, which removes heat from the body.

Another complication: Older people sweat less than they did in their youth, making fans less effective at cooling the body.

Normally, during a heat wave, it is recommended not to do physical activities. However, for an elderly person, even a domestic activity like cleaning can be exhausting. If a fan gives a false impression of coolness, it can be tempting to finish the dishes or do the laundry. This can lead to heat stroke.

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