It’s hot outside — and that’s bad news for children’s health

Reviewed by Emily Henderson, B.Sc.Jun 16 2022

Heat waves are getting hotter and becoming more frequent because of rising rates of air pollution, putting children's health at risk, a wide-ranging new report finds.

A June 15 article in the New England Journal of Medicine reviews current research to take a sweeping inventory of how air pollution and climate change interact to adversely affect people's health, especially that of kids. It examined the link between fossil fuel emissions and a variety of consequences of climate change — including extreme weather events; wildfires; vector-borne illnesses such as malaria, Zika, and Lyme disease; and heat waves, a topic at the forefront of many people's minds.

This month, for example, record-high temperatures have been reported across the United States, affecting more than 100 million people and touching locations from the Gulf Coast to the Great Lakes, the Southwest, the mid-Atlantic, and the Midwest.

In Texas, Austin has already experienced an eight-day streak of temperatures above the 100-degree mark in June, according to the Austin American-Statesman.

These patterns are an important reality to note, said Frederica Perera, the article's lead author. "My concern is that the threats are rising as temperature is rising," Perera, a professor at Columbia University's Mailman School of Public Health, told KHN. "Temperatures are rising because greenhouse gas emissions are rising, and that's a great concern for everyone's health — but especially the most vulnerable."

Children fit into this category, wrote Perera and her co-author, Dr. Kari Nadeau, because their ability to regulate temperature, known as thermoregulation, is not fully developed.

They are also more susceptible to heat-related stress because they're smaller and need to drink and eat more frequently to stay healthy, said Perera. But because "young children are dependent on parents to provide, sometimes their needs go ignored," she said.

The authors noted that heat-related illness is "a leading and increasing cause of death and illness among student athletes" in the U.S. In addition, they cited studies suggesting that "the heat associated with climate change" takes a toll on the mental health of children and adolescents, as well as their ability to learn.

The review article pointed to previous research that associated in utero exposure to heat waves with "increased risks of preterm birth or low birth weight; hyperthermia and death among infants; and heat stress, kidney disease, and other illnesses" among kids.

"Being pregnant is very physiologically demanding in itself, and then heat places additional stress on a pregnant woman," said Dr. Robert Dubrow, a professor of epidemiology at Yale's School of Public Health who was not associated with either study. "And the fetus can experience heat stress as well, which could result in adverse birth outcomes."

And these heat-related risks are across-the-board greater for "low-income communities and communities of color," wrote the authors of the new article.

Carbon dioxide emissions from burning fossil fuels have risen sharply in the past 70 years, according to the article. "Modeling indicates that some heat waves would be extraordinarily unlikely to occur in the absence of climate change," it says.

The authors briefly outline solutions that they describe as "climate and environmental strategies" that "should also be seen as essential public health policy." Beyond big-picture efforts to mitigate fossil fuel and greenhouse gas emissions, they offered various ways to protect children — steps they term "adaptation measures" — which included providing clean water to children and families facing drought or water contamination and creating shaded areas where children play, live, and go to school.

Separately, Austin-based research highlighted why this step could be meaningful.

Researchers tracked the physical activity levels and location of students ages 8 to 10 during recess at three elementary schools in 2019. They compared children's activity at recess during two weeks in September, the hottest full month during the school year, to a cooler week in November. "We wanted to understand the impact of outdoor temperatures on children's play in schoolyard environments," said Kevin Lanza, the study's lead investigator, to inform the design of "future school-based interventions for physical activity in the face of climate change."

During the hotter periods, he said, "children engaged in less physical activity and sought shade."

As temperatures continue to rise, he said, schools must be flexible in making sure students are getting the daily exercise they need. "Schools should consider adding shade, either by planting trees or installing artificial structures, that cover spaces intended for physical activity," said Lanza, an assistant professor at UTHealth's School of Public Health. He also noted that school policies could be updated so that recesses are scheduled during cooler times of the day and moved inside during periods of extreme heat.

But the overall need to protect kids from scorching weather patterns requires action beyond such steps, Perera said, and more climate and clean air policies must be enacted.

"Governments have the responsibility to protect the population and especially those most vulnerable, which especially includes children," Perera said. "Action must be done immediately because we're absolutely heading in the wrong direction."