Track and field Olympian Jenny Simpson collapsed while pacing a mile group at a Sir Walter Miler pop-up event in Raleigh, North Carolina, on Tuesday, per track and field industry website “Let’s Run.”

The 39-year-old did not initially have a pulse after falling down, but it was restored with CPR and an AED, a source confirmed to “Runner’s World.”

“Jenny is receiving excellent medical care, and our thoughts are with her and her family during this time,” organizers with the event wrote on X Wednesday.

“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,” the organizers added in the 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, a three-time Olympian and the 1500-meter world champion in 2011, won bronze in the event at the 2016 Rio Olympics. She also won silver in the event at the world championships in 2013 and 2017.

She has one of the best resumes in U.S. running history.

While running for the University of Colorado, Simpson set six NCAA records won four national championships. She turned pro in 2010.

In 2024, she announced her retirement from competitive racing after competing in the New York City Marathon. She placed 18th.

Simpson finished her professional career with 11 U.S. titles on the track.

However, she has remained active following her retirement.

Recently, she was named Fleet Feet’s first chief running officer.

Simpson has also participated in the Great World Race, competing in seven marathons on seven continents all in a week’s time. She and her husband, Jason, also toured around the country in their motorhome to run races in 2025, per “Runner’s World.”