Extreme heat increases the risk of heart disease

A consequence of climate change is a greater frequency, intensity, and duration of extreme heat events. According to new study published in the Canadian Journal of Cardiology, such events are associated with a greater risk of cardiovascular incidents, particularly in people with preexisting heart diseases.

Extreme heat events pose a significant risk to human health. The heatwave from 2003, for instance, caused 70,000 deaths in Europe, and that from Russia in 2010 caused 55,000 deaths. By conducting a comprehensive review of epidemiological studies, a research team led by the University of Montreal, Canada, has found that heatwaves increase the risk of cardiovascular incidents such as ischemic heart diseases, strokes, or heart failures.

“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 study senior author Daniel Gagnon, a researcher at the Montreal Heart Institute and the University of Montreal. “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.”

According to Gagnon and his colleagues, heat exposure puts too much strain on the heart, especially for people with preexisting cardiovascular disease, and increases the risk of blood clots in the blood vessels supplying the heart.

Preventive strategies to minimize cardiovascular risk during extreme weather events should aim to reduce the extent of dehydration and hyperthermia by insuring that people drink a sufficient amount of cold fluids and ideally have access to air-conditioning.

“Air conditioning is the most effective strategy that can be recommended since it effectively removes the heat stimulus and minimizes the risk of adverse cardiovascular outcomes,” said Dr. Gagnon. “However, less than one third of global households own air conditioning.” Some simple alternatives to air conditioning include electric fan use, skin wetting, or immersing the feet in tap water.

Further research is needed to better understand why heat is linked to cardiovascular disease, how cardiovascular medication affects the body’s physiological response to heat, and what cooling strategies are optimal for individuals with heart disease.

“Cardiovascular health professionals need to be aware of the negative consequences of extreme heat on cardiovascular health. 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,” concluded Dr. Gagnon.

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By Andrei Ionescu, Earth.com Staff Writer