Issue in Review: The Impact of Rising Temperatures on Human Health

June 21, 2024
A hot city

By Sarah Timbie

Summer 2024 is kicking off with an intense heat wave in the U.S. Extremely high temperatures were felt across the South, Midwest, and Northeast last weekend and into the following week, with some areas reaching 100 degrees. On Tuesday morning, June 18, more than 76 million people across the United States were put under heat alerts. Moving into the weekend, the country will continue to heat up, with record-breaking temperatures expected for areas of the Northeast. 

The frequency and severity of heat waves in the U.S. have increased from an average of 2.2 heat waves lasting around three days each in the 1960s to six per season lasting four days each in the 2010s and 2020s. More than 2,300 people died from the effects of excessive heat in summer 2023, and the toll of 2024 is likely to be even worse. This past May has been the twelfth consecutive record-warm month, as global surface temperatures have been the warmest since the earliest recordings in 1850.  

With increased temperatures threatening the health of millions of Americans, it is essential to be aware of the health risks heat poses and who is most vulnerable to their effects. Below, find some recent Rollins research about heat's impacts on health.

Heat Waves Increase Risk of Early-Term Birth

As heat waves become more common and severe, birthing parents are at a higher risk of experiencing preterm and early-term labor. A recent study, co-led by researchers at Rollins, analyzed 53 million births in 50 of the most populous U.S. metropolitan areas from 1993-2017. They found that the rates of preterm and early-term births increased during periods of abnormally high heat. Preterm and early-term births are leading causes of infant mortality and long-term health issues. As heat waves continue this summer, pregnant individuals may benefit from increased attention to keeping cool.

Temperature Variability Increases Risk of Cardiovascular Events

Climate change is causing increased frequency and intensity of heat waves and more dramatic temperature changes. This variation can occur within a single day or over the course of a few days. A Rollins-led study published earlier this year highlights the association between increased variation in temperature over three-day periods and cardiovascular health events, showing the link between heart health and temperature shifts.  Stroke and peripheral vascular disease in particular were highly connected to increased temperature variability. Increased risk of negative cardiovascular health outcomes due to temperature fluctuation is of highest concern during October and March through May, and for populations older than 65 years of age.

As Temperatures Warm, Dementia-Related Hospital Visits Rise

Alzheimer's disease and dementia affect the lives of millions of Americans and their families. Recent research led by Rollins faculty has revealed a possible link between warmer temperatures and an increased risk of negative health outcomes related to Alzheimer’s disease and dementia. While the specific mechanism behind this link is mostly unknown, the results of this study show that people living with Alzheimer's disease or dementia represent a vulnerable population in the context of global warming and could benefit from additional protection from periods of increased heat.

Warmer Outdoor Temperatures Increase the Risk of Snakebites in Georgia

According to the World Health Organization, snakebites are considered a high priority health concern, but research on the environmental risk factors involved is lacking. A Rollins study from last year found a link between a one degree increase in daily temperature highs and an increase in emergency department visits for snakebites from 2014 to 2020. While only a handful of Georgia’s are venomous, the increase in frequency and severity of heat waves may call for keeping a more active eye out for snakes when spending time outside.