Extreme heat hikes heart-linked death risk by 300 percent

March 30 (UPI) -- Hot weather may double or triple heart-related deaths, according to a study published Monday in the journal Circulation.

After reviewing death certificates In Kuwait, a country in which high daily temperatures are the norm, researchers found the number of deaths from cardiovascular disease increased by more than 300 percent on days when the average temperature was 109 degrees Fahrenheit or higher.

Given rising global temperatures, people living in hot regions of the world may be at particularly high risk of heat-related cardiovascular death, researchers said.

"While cardiologists and other medical doctors have rightly focused on traditional risk factors, such as diet, blood pressure and tobacco use, climate change may exacerbate the burden of cardiovascular mortality, especially in very hot regions of the world," study co-author Barrak Alahmad, a mission scholar from Kuwait University and a doctoral candidate in environmental health at the Harvard T.H. Chan School of Public Health in Boston, said in a press release.

The highest temperature on earth in the past 76 years, 129 degrees Fahrenheit, was recently recorded in Kuwait. The average ambient temperature there is 82.2 degrees Fahrenheit.

Extreme heat can cause the body's core temperature to rise. When this happens, the body attempts to cool itself by shifting blood from the organs to underneath the skin. This shift causes the heart to pump more blood, putting it under significantly more stress.

To see how this impacts heart health, a group of cardiologists, environmental health specialists and epidemiologists examined the relationship between temperature and more than 15,000 cardiovascular-related deaths in Kuwait.

All death certificates in the country from 2010 to 2016 that cited "any cardiovascular cause" for individuals ages 15 and older were included in the analysis, which was funded by the U.S. Environmental Protection Agency and the Kuwait Foundation for the Advancement of Sciences.

Compared to days with the lowest mortality temperature -- about 94.5 degrees Fahrenheit -- when the 24-hour average temperature was 109 degrees Fahrenheit or higher, investigators found the risk of dying from any cardiovascular cause was three times higher for the general population. Men were more affected by the extreme temperatures, experiencing a 3.5 times higher death rate, while the death rate among women was nearly 2.5 higher.

Working-age teens and adults between 15 and 64 years of age had a death rate 3.8 times higher on extremely hot days, and the death rate was just over twice as high for people 65 years of age and older.

"The warming of our planet is not evenly distributed. Regions that are inherently hot, like Kuwait and the Arabian Peninsula, are witnessing soaring temperatures unlike ever before. We are sounding the alarm that populations in this part of the world could be at higher risk of dying from cardiovascular causes due to heat," Alahmad said. "Although we cannot conclude it from this analysis, men and working-age people may have been at greater increased risk because of spending more time outside."