Ceiling fans as a sole form of cooling do not do enough to fully ameliorate heat-induced physiological strain for vulnerable populations once the mercury surpasses 31°C.
New Griffith University research set out to evaluate whether ceiling fans reduce core body temperature and physiological strain in bed-resting older adults who had been exposed to prolonged indoor heat of 31°C and 45 per cent relative humidity, typical indoor environments experienced during summer in South East Queensland.
Dr Fergus O’Connor from Griffith’s School of Allied Health, Sport and Social Work said ceiling fan use significantly reduced peak core temperature by 0.2°C, heart rate by five beats per minute, and thermal discomfort, however, heat induced strain was not fully mitigated.
“In ambient conditions of 31°C and 45 per cent relative humidity, ceiling fans were not wholly efficacious and did not fully ameliorate heat-induced physiological strain,” Dr O’Connor said.
“Under the environmental conditions tested, core temperatures were elevated by nearly 1°C and heart rate was elevated by 22 beats per minute, even with the use of a fan.
“Therefore, while ceiling fans offer some benefits, they are not as wholly effective as a standalone cooling mechanism and should be combined with air conditioning, where possible.”
The study advises ceilings fans are best used early during heat exposure and when ambient temperatures are below 33°C.
Setting an air conditioner to around 26°C, coupled with a ceiling fan, was an ideal option to minimise electrical consumption and avoid the negative health effects of heat exposure.
Furthermore, fans can worsen heat strain when the temperature exceeds 40°C, and a common cooling intervention can make your home more like a convection oven than a cool oasis.
People may experience fatigue, dizziness, reduced cognitive function, and if exposure continues, heat-related illnesses.
Dr O’Connor said as climate change drives more frequent and intense heatwaves, and indoor overheating becomes more commonplace, sustainable and accessible cooling interventions such as ceiling fans will play a vital role in protecting people’s health, particularly for older adults.
“However, recommendations for public health guidance should be steeped in interventions which are effective, and not just interventions that will likely not cause harm,” he said.
“Expanding access through government subsidies to enable access to powerful cooling, such as air conditioning, is imperative to protecting the most vulnerable.”
The paper ‘Effects of ceiling fans on core temperature in bed-resting older adults exposed to indoor overheating’ has been published in The Journal of the American Geriatrics Society.
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Fergus O'Connor
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