Montreal Heart Institute-led research has shed light on the impact of electric fan use on older adults in extreme heat conditions. The study found that using a fan at 38 °C and 60% relative humidity led to a modest decrease in core temperature and increased comfort levels. In contrast, using a fan at 45 °C and 15% relative humidity resulted in an increase in core temperature and discomfort.
The Centers for Disease Control and Prevention (CDC) advises against fan use above 32 °C due to concerns that increased airflow could actually accelerate heat gain, especially in vulnerable populations. The study, published in JAMA Network Open, aimed to investigate how fan use and skin wetting affect core temperature, sweating, and thermal perception in older adults during extreme heat exposures.
The research involved 58 elderly participants, including those with coronary artery disease, who underwent heat exposures in a climate chamber set at either 38 °C and 60% relative humidity or 45 °C and 15% relative humidity. The participants experienced different conditions, including control, fan alone, skin wetting alone, and combined fan plus skin wetting sessions.
In the humid chamber, fan use was found to lower rectal temperature, increase sweat rate, and improve thermal sensation and comfort. Skin wetting also had a positive effect on perceptions, and combining both strategies yielded the best results in terms of thermal sensation and comfort without affecting core temperature. However, in the dry chamber, fan use led to an increase in core temperature, higher sweat rate, and worsened perceptions of comfort.
The study concluded that electric fans can be a cost-effective cooling option for older adults during hot, humid weather at 38 °C but should be avoided in very hot, dry conditions. Simple skin wetting can also help manage heat stress while preventing dehydration. These findings could be valuable for public health agencies in refining heat-safety messages for seniors.
Overall, the research highlights the importance of understanding the effects of fan use in different environmental conditions on older adults’ thermal responses and comfort levels. By providing evidence-based recommendations, this study contributes to improving heat mitigation strategies for vulnerable populations during extreme weather events.
