Meanwhile, high blood pressure and blood vessel contractions may increase the risk of a deadly heart attack on a cold day.

The combination of heat and pollution can increase the risk of heart attack as people may breathe faster and harder on hot days. This causes them to inhale more harmful microscopic particles than usual.

Senior study author Yuewei Liu said that another environmental problem around the world is the presence of fine particles in the air. It can interact synergistically with extreme temperatures that are bad for heart health.

Fine particles derived from smoke from fires and emissions from vehicles and industrial facilities are particularly dangerous, as they can reach the deepest parts of the lungs or even the bloodstream. This type of pollution has been linked to heart disease.

“It is also associated with chronic lung disease, premature birth, cancer, and other conditions,” says Liu who is a professor of epidemiology at the School of Public Health of Sun Yat-sen University, Guangzhou, China.

However, this study is considered to have limitations. First, the study did not prove extreme weather or polluted air directly caused cases of deadly heart attacks. The results may also only apply to some regions.

Nevertheless, the study is still important as it raises awareness of exposure to pollution and extreme weather. So does its discussion that climate fluctuations and air pollution may contribute to an increased risk of death.

To stay safe during periods of extreme weather or when air quality deteriorates, it is recommended to stay outdoors as much as possible. Use an air purifier, stay hydrated, and wear a mask.