AJPM: Extreme Weather Conditions Increase Risk of Cardiovascular Disease

Scientists have concluded that extreme weather events—heat, cold, and heavy precipitation—are directly associated with an increased risk of cardiovascular diseases.

The study, published in the American Journal of Preventive Medicine, is based on data from 2015–2020 covering more than 150 cities in China. Researchers used large medical databases and applied causal analysis methods to precisely assess the impact of weather factors on health.

The results showed that extreme heat has the strongest effect: each additional day with temperatures above approximately 38°C increases an individual’s risk of cardiovascular disease by about 3%.

Cold weather also raises the risk, though to a lesser extent—by about 0.1% per day—while heavy rainfall increases it by around 1.6%.

At the population level, this translates into a substantial rise in disease cases: each additional day of extreme heat is associated with more than 1,000 extra cardiovascular cases per 100,000 people.

Researchers also identified high-risk groups. Heat has a stronger impact on pre-retirement-age individuals, smokers, and residents of areas with high air pollution. Cold weather is particularly dangerous for people with excess body weight, as it increases strain on the cardiovascular system by raising blood pressure and blood viscosity.

Interestingly, the effect of temperature depends on how extreme it is: during severe heat, fatty tissue may partially protect the body from overheating, whereas in extreme cold this protective effect disappears and risk instead increases.

The authors emphasize that, in the context of climate change, the number of extreme weather days is increasing, meaning the burden on healthcare systems will also grow. Even a small increase in daily risk can lead to significant consequences at the level of entire cities and countries.