This summer has seen higher than normal temperatures compared to previous years. 

As WSB-TV recently reported, July 3 was the hottest day on Earth since 1979, according to the U.S. National Centers for Environmental Prediction. As more hot weather comes, we must stay safe from the heat and humidity. Dr. Larry Kenney is a professor of physiology and kinesiology at Penn State University. Kathleen Fisher is Dr. Kenney’s Ph.D. student at Penn State University. Together, they explain the caution we must take with our health regarding heat and humidity this season.

“People should be cautious if they’re going outside,” especially if they’re exercising, Fisher said. Being active produces “metabolic heat” in muscles, she explained. And that limits “your ability to tolerate the heat,” she said.

High humidity affects how our bodies naturally operate. Humidity is the amount of water vapor in the air. The primary way the human body releases heat is through evaporation of sweat. According to Fisher, if there is too much humidity in the air, the body cannot evaporate the sweat, which causes more heat to build up. Heat buildup can lead to severe consequences like heat stroke.

When we start to sweat, Fisher said, “The humidity in the air creates a gradient with the water on our skin.” When the air becomes more humid, she explained, that gradient diminishes, and “we have less powerful cooling mechanisms at our disposal.”

Dr. Kenney explains that climate change is the reason for the higher temperatures we received this summer. He elaborates that climate change has increased the frequency and intensity of these sweltering days. Dr. Kenney encourages everyone to stay hydrated and be aware of how long they stay in the heat. 

The Penn State professor discussed the second but more taxing way the body cools down from the heat. The body pumps blood to the skin when it can’t cool down from sweat evaporation. Depending on how hot it is, the body will pump as much blood to the skin as it does for the entire human body. All the extra pumping is taking a significant toll on the heart.

“The other way we deal with increased body temperatures is by pumping blood flow to the skin. This is unique to humans as blood flow goes to the skin and dissipates into the environment. This method puts a great strain on the heart, which can be a hazard to some in vulnerable populations,” said Dr. Kenney.

Two groups of people that need to be closely monitored during the humid heat are infants and older adults. Infants are at the mercy of adults to ensure they are appropriately clothed, fed, and hydrated from the heat. Dr. Kenney shares that infants’ ability to release heat from the body is not developed. Heat-related deaths of infants are tied to adults who don’t make proper decisions. For example, adults who leave infants in the car by accident contribute to that unfortunate statistic.

Older adults are vulnerable to humid heat because their cooling mechanisms are less functional than younger people. Older adults have a lower ability to produce and evaporate sweat, and the second method to cool the body pumps less blood but strains the heart even more. Dr. Kenney reveals socioeconomic factors can play a role in older adults’ vulnerability to humid heat. 

“Socioeconomic factors like lack of access to air conditioning and daily habits make older adults particularly vulnerable to high heat and humidity conditions. Becoming more sedentary and not going outdoors makes older adults vulnerable to heat stroke,” said Dr. Kenney.

This summer’s heat and humidity encourages everyone to take precaution when going outside. This information should not hinder you from enjoying the outdoors but make you prepare enough to hydrate and stay cool while you are stepping out.

Clayton Gutzmore is a freelance journalist in South Florida. He published stories in several news outlets including The Miami Times, 91.3 WLRN, The Atlanta Voice, BET, and Variety Magazine. Gutzmore graduated...