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As climate change makes excessive heat more routine, NC schools forced to weigh student, athlete safety

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This article was originally published by Anne Blythe for North Carolina Health News.

Many children across North Carolina are heading back to school, returning to classes and other activities even as weather forecasters caution about temperatures in the 90s with heat indexes topping 100 degrees.

That can have an impact on football, cross country, tennis and other sports teams that practice and compete in August. It also can have an effect on the mental health and physical well-being of people — from the youngest among us to those with chronic ailments to the older population.

“We think of children, the elderly and people with chronic health conditions as being at the greatest risk,” Daniel Park, medical director of the pediatric emergency department at UNC-Chapel Hill, said during a phone interview with NC Health News. “We should keep an eye on them.”

Ailments caused by excessive heat brought on by climate change can range from skin rashes to cramping and muscle spasms to heat exhaustion and even heat stroke, which can be chronically debilitating or deadly.

Staying hydrated and avoiding prolonged exposure to excessive heat can ward off many of the health issues that are sending people to doctors offices and emergency care facilities.

“From an impact standpoint, heat-related illness is very preventable,” Park said. “Stay cool, stay hydrated, stay informed. I tell people doing these three things is important during these periods.”

This summer, Park said, the pediatric emergency department at UNC Health has seen children come in from sports camps suffering from heat ailments. 

“These are kids that are otherwise healthy,” Park said.

At Duke, J.J. Hoff, an emergency medicine specialist, told reporters during a July 27 webinar that “this summer has been particularly busy. We’ve seen record temperatures that are continuing to climb, so we’re seeing a lot of heat-related illnesses.”

Excessive heat year round, ‘heat seasons’

More troubling than the routine breaking of daytime temperatures this year has been the public health risk created by the steady warming of overnight temperatures, climate researchers and scientists say. When overnight lows are so high, the body doesn’t have time to cool down, making people, especially those in homes without air conditioning, more susceptible to illness and even death.

July 2023 entered the books as the hottest July on record, globally. Antonio Guterres, secretary general of the United Nations, warned that “the era of global warming has ended” and “the era of global boiling has arrived.”   That’s evident in the Southern Hemisphere, too, where they have experienced record heat even though it is winter below the equator this time of year.

“One of the things we’ve talked about with respect to heat over the years is how difficult it is to capture the public’s imagination around heat in comparison to other, like, natural disasters,” Ashley Ward, director of the new Heat Policy Innovation Hub at Duke University, said during a July webinar. “Heat doesn’t typically give you this sort of camera-ready fodder that really motivates people to move like we see with hurricanes or tornadoes or other severe weather.”

“This year Mother Nature has shown us in quite spectacular fashion — through marine heat waves that have sent thousands of dying fish on the shores, particularly on Gulf Coast states, and then bleaching our coral reefs,” Ward added. She referenced “news reports of hikers succumbing to the heat, burn units being filled in places like Arizona with people who are experiencing critical and sometimes deadly burns from contact with pavement and other sorts of structures in our environment” and more.

“We’re continually categorizing this extended period as a heat wave,” Ward said at the July webinar. “At 30 days, we’re not talking about a heat wave anymore. We’re talking about a season. We’re talking about a marker of a shift in our heat regime that we need to pay attention to. This is not an acute event. Typically you think about a three- to five-day event. We’re talking about a chronic, a new chronic, state of being for heat season.”

Unless quick measures are taken to begin to reverse global warming, extreme weather events are likely to become more common, scientists caution, leading to more record-breaking hot periods year after year.

“It isn’t unreasonable to think this could quite possibly be the coolest heat season of our lives,” Ward said.

a table outlining recommendations for athletic activity in the heat. Safe if the Wet Bulb Globe Temperature is under 80, normal practice for temps between 80-85 degrees, reduced intensity for new athletes between 85-88 degrees, caution between 88-90 degrees and suspend practice if above 90 degrees

‘How do you define hot?’

The temperature alone often does not tell the full story when talking about heat waves — or heat seasons, as the more extended periods are being called.

“How do you define hot?” Andrew Pershing, vice president for science at Climate Central, asked during an Aug. 10 SciLive webinar on extreme heat. “It’s actually a thorny question.”

In North Carolina, this past July was not as hot as 2022 and 2019, which were both logged in as the 14th warmest, according to a chart posted by the North Carolina Climate Office. Nor was it as scorching as 2020, the seventh warmest July on record. For anybody who remembers 2016 as a particularly sweltering July, that was the third warmest, the chart shows.

With a diversity of local climates from the seashore to the mountains, some areas of the state felt the heat and humidity more than others. Laurinburg, Rocky Mount and Smithfield were the hottest sites, according to the climate office, reaching 98 degrees on multiple days. Sparta in Alleghany County and Transou in Ashe County in the state’s northwestern corner ranked as the coolest after the temperature dipped to 48 degrees there on July 12.

Despite the range, scientists in North Carolina and elsewhere warn that heat index values are likely to rise as climate change leads to warmer temperatures and higher humidity levels.

The wet bulb globe temperature

The high school football season started this past weekend, with many teams getting a slight break under the Friday night lights from the extreme temperatures that have marked this summer. But in the Triangle region and elsewhere in North Carolina, the heat indices rose to dangerously high levels after several days of relief.

Although other sports teams will be competing and practicing in the weeks and months ahead, the gridiron athletes often get more attention when temperatures top 90 degrees. The players wear shoulder pads, helmets and uniforms with padding. Also, they play on turf that soaks up the heat and radiates it upward. 

Still, runners, endurance athletes, soccer and field hockey teams, and tennis players on hot outdoor courts aren’t immune from the climate effects.

Even though there might have been a time when it was considered a sign of toughness for athletes to push through practices and games in extreme heat, that’s far from the message that health care providers and scientists want to convey these days. Instead, teams stop to take water breaks in the middle of their games.

“This is, I think, more of a personal reflection and a little bit of how I have dealt with heat over my life — and also just watching how it played out in society,” said Pershing, the Climate Central vice president for science. “I think there’s a lot of machismo going on. A lot of people are like, ‘Yeah, I can handle the heat, it’s always been hot, I’m a tough guy.’ Especially guys. ‘Like, I can handle it.’ And so I think we’ve put that on society that this is something that you can just suffer through and man up and it’ll be okay.”

shows a pair of hands holding a weird-looking box-shaped apparatus with a black rubber bulb on top. There's also a white cylinder with a stack of fins on top of the box. The box is used to measure extreme heat.
Wet bulb temperature is measured by a thermometer wrapped in a wet cloth, simulating the cooling effect of sweat. The thermometer is also exposed to the sun, accounting for how it feels in the sunlight. Black globe temperature is measured with the thermometer inside a black globe, replicating how hot it feels in the sunlight.

The Korey Stringer Institute, formed after Minnesota Viking Korey Stringer died from a heat stroke in 2021, has worked to shift that narrative.

The North Carolina High School Athletic Association, which sets policy for and regulates interscholastic athletic programs across the state, has tried to do that, too, by developing heat guidelines for schools to follow.

A certified athletic trainer or first responder must be in attendance at all football practices and games, according to the guidelines. For all sports, the team leaders are expected to keep the conditioning level and medical status of each athlete in mind, adjust intensity levels, insist that athletes begin practices, training and games sufficiently hydrated and take more breaks for fluids and opportunities to get out of the heat.

Janna Fonseca, the health, safety and wellness director of the high school athletic association, said schools are expected to measure the wet bulb globe temperature on the sites where the athletes will be playing or practicing. The Black Globe Thermometer used to get this reading measures the air temperature, humidity, wind speed and sunlight.

That can vary on different parts of a school campus and often offer a more accurate reading on the “feels like” temperature that heat indexes also capture.

When the wet bulb globe temperature is between 85 and 87.9 degrees, new or unconditioned athletes should not practice, according to the NCHAA guidelines. Well-conditioned athletes should have more frequent water and rest breaks with monitoring for heat illness symptoms.

When the wet bulb globe temperature is between 88 and 88.9 degrees, all athletes must be under constant observation and supervision, according to the guidelines, and an immersion pool should be on site for practice.

“We want people to cool first and transport second,” Fonseca said.

Graphic shows how to measure the heat index using a black bulb thermometer. The calculation: 10% of the air temperature plus 70 percent of natural wet bulb temperature plus 20 percent of black bulb temp yields the wet bulb globe temperature.
Image used with permission.

Changing schedules, mandatory water breaks

Practice, according to the guidelines, should be suspended at temperatures of 90 degrees or above. That’s why some teams practice in the mornings before school hours or in the evening after school once temperatures start to go down.

Close monitoring of the temperatures and humidity levels could lead to scheduling changes.

The HighSchoolOT Jamboree start time was delayed a little more than a week ago because of excessive heat. Rules were changed, too, to allow for mandatory water breaks.

Jordan Clark, a postdoctoral associate for the Heat Policy Innovation Hub and the Water Policy Program at the Nicholas Institute for Energy, Environment & Sustainability at Duke University, has studied the effects of extreme heat and spoke recently about the use of the wet bulb globe thermometer, or WGBT, to make high school athletics safer.

“The critical piece here that needs to be far more widespread is taking these measurements on site at the field or the venue where the activity is occurring,” Clark said during the July 27 webinar at Duke. “You often see instances where weather conditions from a weather station that may be located two miles away or 20 miles away are being used. 

“… Having direct measurements on site allows for the most robust way of trying to actually determine how hot is it currently, right here, and what actions can we take to mitigate that.”

Clark elaborated further, saying that it’s easy to feel the different effects of the temperature by moving from the direct sunlight into the shade.

“If you’re standing on a tennis court taking a measurement right there, versus if you’re standing on a grass field taking the measurement right there, they can be quite different and impact the body in much different ways,” Clark said.

That can lead to a shifting of practice sites too.

“Another factor there, especially with understanding how heat is going to vary on something like a football field or a practice field is is knowing that OK, this is what the WGBT is in the sun, but if half of the field is shaded and we move our activity over there, and take a measurement there, that might allow us to do certain things that we would otherwise not be able to do,” Clark added.

A national cooling standard?

In addition to the spotlight on outdoor school activities, there also has been a focus on setting cooling standards that could require air conditioning in school buildings.

“I understand that instituting or implementing a national cooling standard would come at considerable effort and cost,” said Ward, head of the Duke Heat Policy Innovation Hub. “We have a standard that requires that buildings be heated in the winter up to a certain standard. So landlords are required to provide heating for their tenants. Schools are required to have heat. Prisons. You know, all of those populations that I outlined earlier are protected by those heating standards in the U.S. We do not have a cooling standard, and this is challenging.”

The Government Accountability Office estimated that there are some 35,000 school systems in the U.S. that do not have adequate cooling systems — or have none at all, Ward pointed out. Some school systems have questioned the need for air conditioning given that many are closed in the summer. But there can be hot spells in April and May as school winds down and the climate changes. More often than not, there are few cool days in August and September, as the school year starts again.

Last week, when the heat index topped 100 degrees, Southeast Raleigh Magnet High School dismissed classes early due to problems with the air conditioning system.

Practically speaking, Ward said, most of the funding to equip schools with cooling systems would come from local budgets. In North Carolina, most school systems get state and county funds.

“I say that, but I also want to point out Scotland County, one of the poorest counties in the state, implemented universal air conditioning in all of their schools,” Ward added. “So it is possible to do even on a limited budget.”

If the federal government were to put a minimum cooling standard in place, Ward said, states could then put in levels required above that. That must be done in conjunction with how the cost could be “properly implemented,” she added.

“Along with something like a cooling standard, there needs to be a process through which either funding or innovative financing methods can be deployed to help people comply,” Ward said.

This article first appeared on North Carolina Health News and is republished here under a Creative Commons license.

North Carolina Health News is an independent, non-partisan, not-for-profit, statewide news organization dedicated to covering all things health care in North Carolina. Visit NCHN at

Anne Blythe

Anne Blythe writes about oral health care, children’s health, and other topics for North Carolina Health News.