Science has debunked public health advice on using electric fans during heatwaves

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The use of electric fans, contrary to official health recommendations which indicate the extra airflow will just bake you faster, does help protect against heat-related illness, according to a study by the University of Sydney.

The current thinking is that fans are dangerous in heatwaves, when the temperature rises above 35C.

However, the landmark study, published in the Journal of the American Medical Association, calls for a rethink of public health advice on coping with extreme temperatures.

Dr Ollie Jay, from the University of Sydney’s Faculty of Health Sciences, said electric fans are a simple and cost-effective tool for preventing heat related illness and current guidelines are putting the public at risk.

“Older people in particular are at risk of heat stress and heart attacks during hot weather and sometimes a fan is the only cooling device they can afford,” Dr Jay said.

“The current guidelines are based on an outdated theory that fans are dangerous when air temperatures exceed skin temperature, like the idea of a turkey cooking faster in a fan assisted oven.

“This doesn’t take into account that airflow created by a fan increases the evaporation of sweat from the skin, which is one of the key ways in which our bodies cool down.”

Using a controlled heat chamber, Dr Jay’s team and colleagues from the University of Ottawa (Canada) and Loughborough University in the UK, examined the effect of fans in conditions which cause rapid increases in heart rate and body core temperature.

They found fans were beneficial at 42C or 108F, up to seven degrees higher that the 35-37C recommended by the world’s major public health agencies, including the World Health Organisation (WHO).

“The participants actually had a lower heart rate using a fan at 42 degrees than they had without a fan at 36 degrees,” said Dr Jay.

Further human studies are planned to confirm these results and investigate the effect of fans in different types of heatwaves, with conditions ranging from dry heat to high humidity.

With a recent report from the Climate Council suggesting heatwaves in Australia are becoming hotter and more frequent, Dr Jay said it is important people know about the protective benefits of fans.

“Heatwaves claim lives every year so it’s essential that people who can’t afford air-conditioning know that a fan is a good alternative and could even save lives,” he said.

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