A new study has highlighted a concerning link between rising temperatures and an increased risk of heart disease in Australia, with heatwaves becoming more frequent and intense as the climate changes.
Despite the onset of autumn, Australia has continued to experience extreme heat, with temperatures soaring by up to 15 degrees above average in some southeastern regions on Saturday. These heatwaves follow the hottest spring and summer on record, with national mean temperatures exceeding pre-industrial levels by more than two degrees Celsius.
According to new research, these extreme heat trends are already responsible for 7.3% of Australia’s heart disease burden. If current greenhouse gas emission trends continue, that figure could potentially double or even triple by mid-century.
Heat’s Impact on Heart Health
Cardiovascular disease remains the leading cause of death globally, including in Australia. In 2023, ischaemic heart disease, a form of cardiovascular disease, was responsible for 9.2% of all deaths in the country, with over 35,000 lives lost.
A recent peer-reviewed study, conducted by Australian universities and published in the European Heart Journal, has found that the risk of heart disease rises with higher temperatures. The research analyzed data from 2003 to 2018 and revealed that heat contributed to more than 48,000 years of life lost annually due to cardiovascular disease.
Lead researcher Professor Peng Bi, a public health and environmental medicine expert at the University of Adelaide, explained that hot weather forces the heart to work harder to regulate body temperature. This added strain can be particularly dangerous for individuals with pre-existing cardiovascular conditions.
Regional Variations in Heart Disease Burden
To assess the current impact of heat on cardiovascular health, the researchers examined data from the Australian Burden of Disease Database. They also projected how the burden might evolve under different climate scenarios, factoring in population growth, demographic shifts, and heat adaptation strategies.
The study identified significant regional differences in the impact of heat on heart health. South Australia had the highest rate of cardiovascular disease attributable to high temperatures, followed by Victoria. These regions, which are more vulnerable to extreme heat, were expected to continue facing the highest rates of heat-related heart disease into the 2030s.
The Northern Territory, which has a consistently warm climate, currently has the lowest rate of heat-attributable cardiovascular disease. However, the study predicts that the territory will experience the most significant future increase in cases, potentially leading to the highest rate of heat-related heart disease by the 2050s.
Future Projections and the Role of Climate Change
The study also assessed the impact of future climate scenarios, drawing on data from the Intergovernmental Panel on Climate Change (IPCC). According to the research, if global emissions stabilize, the number of disability-adjusted life years (DALYs) lost to heart disease could increase by 83.5% by 2030. If emissions continue to rise, this could increase by up to 92.7% in the next five years, with a “severe scenario” predicting a staggering 182.6% rise by 2050.
Last year, 2024 marked the first calendar year in which global temperatures surpassed 1.5°C above pre-industrial levels, contributing to an increase in extreme heat events. The findings of the study underscore the growing urgency to address climate change and its impacts on public health.
The Need for Adaptation Strategies
The researchers emphasized that while future projections carry inherent uncertainty, there are opportunities to mitigate the impact of heat on heart disease through strategic adaptation. Investment in urban cooling initiatives, public health campaigns, and enhanced emergency responses to hot weather could drastically reduce the number of heat-related cardiovascular cases.
Professor Bi stressed the importance of taking preventive measures during heatwaves, particularly for vulnerable groups. “As climate change brings more frequent and intense heat, the risks associated with higher temperatures are likely to increase. Staying hydrated, seeking cool environments, and getting medical help when necessary are essential precautions,” he said.
The study was conducted by experts from the University of Adelaide, the University of Sydney, the Australian Institute of Health and Welfare, and Monash University, with funding from the Australian Research Council Discovery Program.
While the study’s focus was on Australia, the researchers noted that its findings are relevant to other parts of the world grappling with the impacts of climate change.
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