Dr. Eliza Pierko’s run in the Berlin Marathon two weeks ago was going “amazingly well” as she neared the end and was on pace to crush her personal record.As she approached the 21.5 mile mark of the 26.2 mile race, Pierko, a Loyola Medicine sports medicine physician, noticed a fellow runner to her left who was on the ground and not moving.She stopped to help the man, who appeared to be in his 60s, she said. She found a pulse on his neck, but he was unresponsive.“Then, all of a sudden he turned blue in front of my eyes, and I lost the pulse,” Pierko said. “I had enough time to shout to all the bystanders that he was in cardiac arrest, and I was going to start compressions.”One of the bystanders had already called for an ambulance.Runners continued jogging by, some briefly stopping before resuming their run, as Pierko performed CPR on the man while still on the course, off to the side.Other spectators gathered around, including one group who held a blanket around Pierko and the man to shield them from other bystanders.“I was able to do maybe half of the cycle of the CPR by myself and then another bystander took over, and we continued to do compressions and rescue breaths,” Pierko said.Paramedics arrived with a defibrillator about two minutes later. They placed the defibrillator pads on the man and shocked him, causing his heartbeat to return to a normal rhythm. He began to breathe again, and his skin color returned to normal.At that point, Pierko was comfortable that he was “in safe hands,” and so she decided to continue the marathon as the man waited with EMS to be taken to a hospital. In all, Pierko had stopped her race for about four minutes and 20 seconds to help the runner, she said.“It was hard initially,” Pierko said of resuming the race. “My entire body was numb, I was running on the adrenaline.”Her watch showed her heart rate at 185 beats per minute, “which was way higher than where my heart rate while running the marathon is.”Pierko finished the remaining 4.7 miles of the marathon, held Sept. 29.Nevertheless, she beat her personal record marathon time by two minutes and 53 seconds. Her total time was 4:28:55.The man she helped during the race survived, but Pierko has not heard any other updates on his condition and has not spoken with him. Dr. Eliza Pierko, a Loyola Medicine sports medicine physician, finished the Berlin Marathon with her personal best record time after stopping mid-race to help save a man in cardiac arrest.Provided Pierko, who often works as the on-site physician at sporting events, has done CPR before but never at a game or in a situation like the one she faced in Berlin.“I was more used to these situations in a hospital setting where I have a huge team helping out, and the crash cart and the AED and everything else is at my disposal, but it never happened to me, especially as I’m racing something,” Pierko said.The Berlin Marathon was her fifth marathon, and it was her first since suffering an ankle fracture last year. She has run the Chicago Marathon twice, but she will not participate in Sunday’s race.For any of the 50,000 runners expected to participate in the 46th Chicago Marathon Sunday, Pierko advised them to “take it easy, start slow.”“If they are having shortness of breath or chest pains, they should stop immediately and call for help because these can’t be overlooked, and those runners do need to be seen by a medical professional,” Pierko said.She also reminded runners to fill out the medical information on the back of their runner’s bib, which can include emergency contacts and other medical background, because, she said, “It can honestly save your life.”