New research conducted by the University of Sydney and the Montreal Heart Institute has found that using a fan in hot and humid weather can reduce cardiac strain in older individuals, contrary to recommendations from the Centers for Disease Control and Prevention in the US. The study, funded by the National Health and Medical Research Council (NHMRC), focused on low-cost cooling strategies for older adults, who are more susceptible to health risks during hot summer weather. Professor Ollie Jay, Director of the Heat and Health Research Centre, emphasized the importance of understanding the impacts of different cooling strategies on the heart to help vulnerable individuals stay well in extreme heat conditions.
The study involved exposing older participants with and without heart disease to two different environments: one hot and humid (38°C and 60 percent humidity) and the other very hot and dry (45°C and 15 percent humidity). These conditions were chosen to represent the two most common heatwave extremes globally. In hot and humid conditions, fan use with and without skin wetting was found to reduce heat-induced cardiac strain in older individuals. However, in very hot and dry conditions, fan use had an adverse effect by increasing cardiac strain, potentially leading to fatal consequences for individuals with heart disease. In these conditions, skin wetting alone was found to be effective in reducing the heart’s workload.
Co-author of the study, Dr. Daniel Gagnon from the Montreal Heart Institute, highlighted the significance of low-cost cooling alternatives for individuals who do not have access to air conditioning, especially those who are most vulnerable to heat stress. The study’s findings indicate that the type of cooling strategy to use depends on the weather conditions, providing valuable information for older people to stay safe during heatwaves. Dr. Georgia Chaseling, a post-doctoral researcher who led data collection in Montreal and now co-leads the “Ageing and Chronic Diseases” research theme at the University of Sydney, emphasized the simplicity of the interventions tested, which aimed to determine effective solutions for individuals in low-resource settings without air conditioning.
As health hazards from extreme heat become more common due to climate change, older adults, particularly those with heart disease, face increased risks from hot temperatures. Understanding the effects of different cooling strategies on the heart is crucial for protecting vulnerable individuals during hot summer weather. The study’s findings demonstrate that fan use with skin wetting can help alleviate heat-induced cardiac strain in hot and humid conditions, while skin wetting alone is more effective in very hot and dry conditions. These insights provide valuable guidance on appropriate cooling strategies for older individuals in various heatwave scenarios, promoting their safety and well-being during extreme weather events.
The research highlights the need for tailored cooling solutions for older individuals, considering their heightened health risks during hot weather. While air conditioning is an effective cooling method, it may not be available to everyone, particularly those most vulnerable to heat stress. The study’s focus on low-cost cooling strategies offers hope for older individuals who do not have access to air conditioning, providing effective alternatives to stay cool and reduce cardiac strain during heatwaves. By understanding how different weather conditions affect the effectiveness of cooling strategies, older individuals can make informed decisions to protect themselves during extreme heat events and minimize the risks associated with high temperatures.
