AUSTIN (KXAN) — Paramedics were sent to the 3M Half Marathon for reports of two runners suffering cardiac arrest Sunday morning.

Austin-Travis EMS said the call for the first patient came in at 9:48 a.m. He was located at the intersection of East 32nd Street and Duval Street. The second runner, also a man, suffered a cardiac arrest at the finish line. Both men are said to be in their 40s.

Emergency medics were able to get a pulse on both runners. They were taken to St. David’s Medical Center in critical condition.

Denise Rozier, who lives in Buda, was waiting for her sister at the finish line when she saw one of the runners collapse.

“One minute he’s healthy, he’s running. And the next minute he’s right in front of us and he’s dying,” Rozier says.

“You could just see he was lifeless.”

Rozier says paramedics were on-scene quickly and she recorded video of them administering CPR.

“Oh Jesus, please God,” Rozier says during the video recording.

“I immediately just started praying because I just didn’t want to see this man die at a marathon on a beautiful Sunday morning,” she remembers.

First responders were able to resuscitate both patients this morning before taking them to the hospital.

“Eventually I saw his chest rise by itself,” Rozier says.

She and a spokesperson for the event are thanking medical personnel tonight.

“I saw this man who had no breath, no heartbeat, go from that to breathing on his own. I saw his chest rise and I just breathed a sigh of relief because if they weren’t there, I mean, I can’t even begin to imagine,” Rozier says.

While it’s unknown how experienced either of the patients were when it comes to races, a spokesperson for the American Heart Association says if you’re inexperienced, it’s best to ease into long-distance courses.

That means typically training for about five months before stepping onto the starting line.

The AHA says although cardiac arrest occurs in only about 1 in 50,000 runners, a high proportion of all exercise-related cardiac events occurs during marathon length races.

Event organizers sent this statement to KXAN News:

“Although there were countless positive moments from today, like first-time finishers, hundreds of 13.1-mile PRs, and thousands of goals met, unfortunately two participants were transported to local hospitals. Those participants received immediate medical attention because of our strategic and proactive planning and great working relationship with medical personnel. Any additional medical updates will need to be provided by immediate family.”

The science

The American Heart Association refers to a 2018 study:

Researchers discovered evidence that sparked a controversy among runners: Could the longer distance of a marathon be harmful to an amateur runner’s cardiovascular system?

In the study, heart strain was compared in 21 groups of three runners after each ran different lengths of races – a full and half marathon and a 10k race.

All study subjects were considered amateur runners; non-professional finishers with less than three years of experience.

The researchers determined there was minimal difference between groups when it came to long-term cardiovascular risk, but the longer distance put a much greater immediate strain on their hearts.

The AHA says: What does this mean for the casual runner? If you have the hankering for a long run, start with the shorter length endurance races, like a 5k, 10k, or half marathon, to protect the heart from strain.

And remember, this does not give you permission to move less! We all need to aim for the physical activity recommendations of 150 minutes of moderate or 75 minutes of vigorous physical activity throughout each week.

For more on this study, click here