The day the heat stopped a road race famous for its heat and humidity

Despite a decision to halt the The Atlanta Journal-Constitution Peachtree Road Race due to high temperatures, race organizers say the race is safe and that they will continue to discuss ways to ensure runners can keep enjoying the 55-year-old road race in a warming climate.

About 44,000 runners, walkers, rollers and meanderers perspired through high temperatures and humidity down Peachtree Street for 6.2 miles to reach Piedmont Park. Thousands safely finished the course, but after the sun came out, race organizers say conditions worsened. The medical tent became very busy, fueled by a “surge” of runners who had already finished needing medical attention inside the park, according to Rich Kenah, director of The AJC Peachtree Road Race and CEO of the Atlanta Track Club.

It was a combination of events — that surge at the medical tent, plus humidity and direct sunlight on the course and the 90 degree temperature at the finish — that led race organizers at 10:42 a.m. to issue a “black flag ” warning of dangerous conditions. Race organizers with the Atlanta Track Club stopped recording any official race results. The estimated 1,000 participants still on the course were allowed to finish, and race officials continued to provide water and medical support along the route.

Heat and humidity — along with the course’s hills, one known affectionately as “cardiac hill” — have always challenged Peachtree runners. But federal data shows the temperatures athletes are often encountering on race day have risen since 1970, when the road race was first held. The rising temperatures are seen as evidence of man-made climate change.

“Yesterday it was hot and humid for longer,” said Jacque Hartley, a longtime fan of the race. The humidity was the key, she said, making it more difficult to cool down through sweat evaporating. “You literally sous-vide yourself,” she said. “You roast yourself because the water stays on your body and doesn’t do the thing that sweat is supposed to do, which is to cool you.”

Kenah said race organizers will do an after-action analysis, as they do every year. But the data doesn’t point to canceling the July 4 event or moving it, he said Friday. “That would be silly.”

“We need to evolve,” Kenah said. “We need to hold on to the traditions that make Peachtree special. But we need to monitor the data and make adjustments.”

Numbers aren’t final, but Kenah said there were about 240 people seen for medical needs, including some cases of heat exhaustion. About 20 people were taken to hospitals for issues including one suspected cardiac arrest. All that is about average, Kenah said. The person with a suspected cardiac arrest is doing well in the hospital, he said. No one has died at the race in the past decade and since its founding, the event has had “less than five” deaths, he said; none due to heat-related illness.

Brian Stone, a professor at Georgia Tech and director of the university’s Urban Climate Lab, said the Peachtree Road Race takes place in an unusually hot location, even for Georgia. The race’s start line near Lenox Square is located in one of the hottest pockets of the city , research by Stone’s Urban Climate Lab has found, and the course down Peachtree Road traverses what Stone says is the heart of the city’s heat island.

“Temperatures in this area are going to be the hottest we find in Atlanta on any given day,” Stone said. With heat risk expected to grow, Stone said he thinks it’s likely Peachtree organizers will have to adjust the race to protect human health — either by shifting the start time earlier, or perhaps considering an alternate date.

“I don’t think most Atlantans have seen the patterns of their life shifted by rising temperatures yet in a profound way,” Stone said. “But I’d say we’re entering a period where that’s going to increasingly be true, particularly with athletics and outdoor activities.”