A series of recent studies predict a significant increase in cardiovascular deaths due to extreme heat in the coming decades, with older and Black adults being disproportionately affected. The studies, supported by the National Institutes of Health, the American Heart Association, and the National Heart, Lung, and Blood Institute, used county-level data from 48 states between 2008 and 2019, and models for future greenhouse gas emissions and future socioeconomic and demographic makeup of the U.S. population.
The research found that extreme heat currently accounts for less than 1% of deaths caused by heart disease. However, as the number of summer days with a heat index above 90 degrees Fahrenheit increases, so will the number of fatal heart attacks, strokes, and arrhythmias where heat plays a role. The studies suggest that extreme heat can impact heart health through increased heart rate, changes in blood pressure, and increased inflammation.
From 2008 to 2019, extreme heat was associated with 1,651 excess cardiovascular deaths per year. Projections indicate that by mid-century, extreme heat could be associated with 4,320 to 5,491 excess deaths annually, depending on greenhouse gas emissions. These deaths could rise by 162% to 233% from 2036 to 2065.
The studies also highlight the need for 'heat action plans' to protect high-risk communities from heart risks and suggest that more aggressive policies to reduce greenhouse gas emissions have the potential to reduce the number of people who may experience the adverse health effects of extreme heat. The research underscores that climate change is a health equity issue, as it will impact certain individuals and populations disproportionately.