New collaborative research indicates that utilizing a fan during hot and humid conditions can lessen cardiac strain in older adults, which goes against the guidance provided by the Centers for Disease Control and Prevention (CDC) in the United States. The study explored various affordable cooling methods, such as electric fans used alone or with water sprayed on the skin, specifically targeting older individuals who face increased health risks in high temperatures.
Recent research from the University of Sydney and the Montreal Heart Institute reveals that employing a fan in hot and humid weather reduces heart strain in older adults, opposing recommendations from the CDC in the US.
Conducted with funding from the National Health and Medical Research Council (NHMRC) and published in the New England Journal of Medicine, the study examined the effectiveness of low-cost cooling methods, including using electric fans with and without skin moisture, aimed at older adults particularly susceptible to health issues during sweltering summer weather.
Professor Ollie Jay, the Director of the Heat and Health Research Centre and Thermal Ergonomics Laboratory in the Faculty of Medicine and Health, noted: “The risks associated with extreme heat are becoming more prevalent due to climate change. Older adults, particularly those with heart conditions, face elevated risks because of the stress that high temperatures place on the heart. It is essential to understand how different cooling methods affect the heart to help those at risk remain healthy during hot summers.”
The study involved older participants with and without heart disease being tested in two different environments: one hot and humid (38°C with 60% humidity) and the other extremely hot and dry (45°C with 15% humidity), reflecting the two predominant heatwave scenarios globally.
Findings indicated that using fans in hot and humid settings, whether or not combined with skin wetting, effectively diminished heat-related cardiac strain in older individuals.
Conversely, in extremely hot and dry conditions, using a fan actually exacerbated cardiac strain, potentially putting individuals with heart disease at serious risk. While fans can aid in evaporating sweat, their benefit is limited in dry heat and is often overwhelmed by convection, which can draw more heat into the body. In these dry conditions, simply wetting the skin proved to be an efficient method for reducing heart workload.
Co-author Dr. Daniel Gagnon from the Montreal Heart Institute emphasized: “Air conditioning is an effective cooling option; however, it’s not accessible to everyone, particularly those who are most vulnerable to heat, such as the elderly and individuals with heart conditions. Thus, it’s encouraging to find that affordable alternatives can also be effective.”
“Significantly, our research demonstrates how weather conditions influence which cooling strategies should be implemented, providing crucial information to assist older individuals in staying safe during heatwaves.”
Dr. Georgia Chaseling, who oversaw data collection in Montreal during her time as a post-doctoral researcher and now co-leads the “Ageing and Chronic Diseases” priority research theme at the Heat and Health Research Centre at the University of Sydney, added: “The methods we examined may seem basic, but that was intentional, as we aimed to identify which solutions those in low-resourced environments with no access to air conditioning should utilize or avoid.”
