Jenny Simpson, a three-time Olympian and one of the most accomplished American female runners in history, was taken to hospital and is receiving treatment after collapsing at a track event on Tuesday in North Carolina.

The organizer of the event, Sir Walter Running, said there had been a “medical incident” involving Simpson while she paced a mile group at an event in Raleigh. Runner’s World and LetsRun reported that Simpson did not have a pulse for a period of time but said it was restored with CPR and an AED.

“We are incredibly grateful to the individuals who responded immediately, as well as EMS and the medical professionals who handled the situation with such care, urgency, and professionalism. Jenny is receiving excellent medical care, and our thoughts are with her and her family during this time,” Sir Walter Running said in a statement.

“We are also thankful to everyone who has reached out with concern and support. We ask that you continue to keep Jenny and her family in your prayers as we all hope for the very best.”

Simpson, 39, represented the United States at three Olympics in Beijing, London and Rio de Janeiro, winning bronze in the 1500m in 2016. At the time, she was the first American woman to medal in the event.

She was the 2011 world champion in the 1500m and later won silver medals in the event at the 2013 and 2017 world championships. She claimed 11 US titles before retiring from competitive running in 2024.