Two studies have found profound effects hot and cold environments can have on the body’s cardiovascular system.

The results, which were published in the journals Scientific Reports and Experimental Physiology, are especially worth looking into, given the ongoing climate crisis humans are subjected to.

As the world has already experienced, the climate crisis is aggravating heat waves to become more frequent, longer, and more intense. These heat waves alone are responsible for more deaths than natural disasters, according to MedicalXpress.

Moreover, a rise in energy costs due to the energy crisis has led to many households slashing their heat expenditure or completely stopping it to heat their homes.

"In both studies, we replicated real-world environmental temperatures the body might be exposed to and were able to show physiological responses that could help explain known seasonal variations in cardiovascular deaths," physiologist Justin Lawley from the Department of Sport Science at the University of Innsbruck said, according to the outlet.

In the study investigating the role of heat waves on industrial workers’ health, seven male participants were observed for nine consecutive regular workdays in a controlled laboratory setting. During the study, participants were made to do daily tasks to mimic typical industrial work.

Even relatively mild heat waves result in increased core and skin temperatures along with an increase in skin blood flow, according to the outlet. These physiological reactions are essential to keep the body from overheating at rest. However, when standing, the body must maintain internal temperature as well as maintain blood pressure to prevent fainting, the study found. This burdens the cardiovascular system.

"These responses reflect the stress on the cardiovascular system that industrial workers face during heat waves, which can lead to heat illness, fainting, and even potentially death due to accidents or serious medical complications in persons with underlying cardiovascular disease," Lawley emphasized.

For the second study, researchers examined the effect of mild cold exposure on the cardiovascular system and focused on finding mechanisms that are responsible for the increase in blood pressure.

In the study, the skin temperature of 34 participants was cooled down from a normal 32-34 degrees to about 27 degrees with ten degrees of cold air. Once, the entire body was cooled and in the next instance, just the face was cooled.

"We observed that when the entire surface of the body is cooled, blood pressure increases mainly due to an increase in vascular resistance of the skin, although there was also a slight reflex increase in resistance of the blood vessels inside the skeletal muscle,” Lawley said.

“However, importantly, when only the face was cooled, we saw a very similar increase in blood pressure that was due to a reflex increase in vascular resistance of the skin throughout the whole body," Lawley added.

The results highlight the importance of protecting the face from cold and not just the body, even in the mild cold temperature of ten degrees.