A recent study investigated how electric fans influence the body core temperature and heart rate of 18 elderly participants aged between 65 and 85 years. They were subjected to a simulated extreme indoor climate of 36 degrees Celsius and 45% relative humidity for a duration of eight hours. The findings indicated that fan usage did not have any significant effect, as all three tested conditions resulted in an average body core temperature of 38.3 degrees Celsius and a heart rate of 100 beats per minute.
On sweltering summer days, electric fans alone offer minimal cooling relief for older adults indoors, largely due to their diminished ability to sweat, which can create oven-like conditions inside.
A recent study published in the Journal of the American Medical Association looked at the effects of electric fans on body core temperature and heart rate among 18 individuals aged 65 to 85, exposed to a simulated extreme indoor temperature of 36°C with 45% humidity for eight hours.
The participants were observed on three separate days: one day without a fan, another with a fan blowing at two meters per second (the typical speed of a household fan), and the final day with a fan on high speed at four meters per second.
The results indicated that fan usage did not significantly change participants’ physiological responses, with average body core temperatures at 38.3°C and heart rates at 100 beats per minute across all conditions.
Though there was a slight improvement in perceived comfort, there was no meaningful decrease in physiological strain.
Dr. Fergus O’Connor, the lead researcher from Griffith University’s School of Health Sciences and Social Work, noted that older adults struggle to regulate their body temperature in extreme heat.
“As we age, our ability to sweat declines, diminishing the effectiveness of electric fans,” he explained.
“This decline can start as early as our 30s or 40s, but there is a marked impairment by the time we reach our 60s.
“Moreover, older adults often have a reduced ability to perceive heat stress, which can lead to serious health risks.”
In Australia, extreme heat claims more lives than any other natural disaster combined, with over 100 fatalities annually in Queensland alone due to high temperatures.
The inability to maintain cool environments can result in heat cramps, heat exhaustion, and heat stroke.
“As heat events become more common, these findings stress the importance of developing effective and sustainable cooling solutions tailored to the needs of older individuals,” Dr. O’Connor mentioned.
“Especially in the southern regions, where hot, dry days can reach around 42°C with only 10 to 15% humidity, any perspiration quickly evaporates.
“In these situations, using a fan merely circulates hot air over dry skin, exacerbating heat effects. However, in more humid areas like tropical Queensland, a fan can assist in evaporating moisture from the skin and provide some cooling, provided the ambient temperature is not excessively high.”
Dr. O’Connor concluded that the research showed fans, as a standalone cooling option, do not significantly alleviate heat discomfort in conditions typical of a Queensland summer—36°C with 45% humidity, yet they do not seem to exacerbate heat strain either.
“Many individuals may hesitate to use air conditioning due to the high costs, so it’s vital to explore more economical air conditioning methods,” he suggested.
“Rather than setting the temperature extremely low for an ice-cold environment, consider setting it a bit higher, such as around 26 or 28 degrees.
Combining air conditioning at a higher temperature with a fan can deliver cooling comfort while significantly lowering cooling costs.”
