Three-time U.S. Olympian Jenny Simpson announced her running career is over after suffering sudden cardiac arrest following a track event in June. The 39-year-old collapsed after pacing runners at the Sir Walter Running Pop-Up Mile in Raleigh, North Carolina, where CPR was performed immediately and an AED was used until emergency medical personnel arrived.

Her condition worsened at the hospital—she suffered another cardiac arrest and was placed on life support before being transferred to Duke Hospital for advanced treatment. “Miraculously, my heart woke back up,” Simpson wrote on Instagram. She was later diagnosed with Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC), a rare inherited condition in which scar tissue disrupts the heart’s electrical system.

Now back home in Colorado, Simpson called her situation the “best-case scenario” and will continue working with her Duke medical team. But the diagnosis makes returning to running dangerous. “That chapter has ended,” she wrote. “Thankfully, my story hasn’t.”

Her career spanned three Olympics, including an Olympic bronze medal and a world championship title in the 1500 meters. She stepped away from professional racing after the 2024 New York City Marathon and became Fleet Feet’s chief running officer—a role that lets her keep helping others find confidence, connection, purpose, and joy in the sport.