Cardiovascular Health at Risk During Extreme Heat Events

Extreme heat events, which are increasing in frequency and intensity as a consequence of global warming, are associated with an increased risk of adverse cardiovascular incidents, especially for adults with pre-existing cardiovascular diseases, according to a study published in the Canadian Journal of Cardiology.

“The Intergovernmental Panel on Climate Change (IPCC) recently reported that global temperatures are rising at a greater rate than previously projected, and that the number of extreme heat days will significantly increase across most land regions,” said Daniel Gagnon, PhD, in a press release. “Although we don’t yet fully understand the reasons, people with cardiovascular disease are at greater risk of hospitalizations and death during extreme heat events.”

The investigators conducted a comprehensive review of epidemiological studies, finding a consistent association between extreme heat and a greater risk of adverse cardiovascular outcomes. Further, after reviewing prior systematic reviews and meta-analyses considering the effect of extreme heat on adverse cardiovascular outcomes, they concluded that heatwaves significantly increase the risk of death from ischemic heart disease, stroke, and heart failure.

“Although the effects of extreme heat on adverse cardiovascular events have been explained in the context of heatstroke, many events occur without heatstroke, and the mechanisms of these events in the absence of heatstroke remain unclear,” Gagnon said in the press release. “It is likely that heat exposure increases myocardial oxygen needs.”

While air conditioning is the most effective strategy for managing heat exposure during extreme heat events, the study authors note that less than one-third of households globally own air conditioning. Potential alternatives include electric fan use, skin wetting and immersing the feet in tap water.

The investigators note that more research is necessary to understand the association between extreme heat and a greater risk of adverse cardiovascular outcomes, as well as the effect of cardiovascular medication on the human body’s physiological responses during heat exposure. It is possible that heat exposure puts too much strain on the heart for individuals with heart disease and that heat exposure increases the risk of blood clots forming within the blood vessels that supply the heart, according to the study authors.

“Cardiovascular health professionals need to be aware of the negative consequences of extreme heat on cardiovascular health,” Gagnon said in the press release. “A better awareness and understanding of the cardiovascular consequences of extreme heat, and of the measures to take to prevent and mitigate adverse events, will help us all assess the risk and optimize the care of patients exposed to an increasingly warm climate.”

REFERENCE

Experts warn that extreme heat events jeopardize cardiovascular health. News release. EurekAlert. November 18, 2021. Accessed November 18, 2021. https://www.eurekalert.org/news-releases/935146