SEOUL, Oct 14 — South Korean running influencer and artificial intelligence semiconductor researcher Yoo Ji-won has died after collapsing during the 2026 Seoul Race, according to Resonate Voices.
She was 25 years old and was a graduate student at the Korea Advanced Institute of Science and Technology (KAIST).
Yoo lost consciousness at the 20.6-kilometre mark of the 21-kilometre half-marathon course, roughly 500 metres from the finish line.
“At around 8.49am on October 11, an emergency situation occurred when a participant in the half course collapsed at the 20.6km mark,” the organising committee stated.
“After immediate first aid on site, the participant was transported to a medical facility by 119 ambulance for treatment, but unfortunately, passed away.”
Medical authorities have not confirmed an official cause of death.
The Seoul Race Organising Committee confirmed the fatality in an official statement to participants on Monday and extended its support to her family as investigations continue.
“We respectfully pray for the deceased’s peaceful rest and extend our deepest sympathies to the bereaved family facing this sudden sorrow,” the statement added.
“We will carefully examine this incident and proceed with necessary follow-up measures without fail.”
Yoo, who was born in 2001, earned wide admiration in South Korean running circles for combining elite athletic endurance with demanding scientific research at KAIST.
She began distance running in 2022 and cultivated a devoted online following by documenting her training alongside her laboratory work on next-generation computing hardware.
Her performances established her among the country’s leading amateur long-distance runners.
On March 15, 2026, Yoo finished the full Seoul Marathon in two hours, 56 minutes and 32 seconds.
That result secured her a “sub-3” marathon finish — a highly prized standard achieved by very few non-professional runners.
She had earlier claimed victory in the women’s masters 10-kilometre category at the Gunsan Saemangeum Marathon in the spring.
After her collapse, false claims spread on social media suggesting hospital staff had treated and released her to recover at home.
Friends and running partners stepped in online to set the record straight and appealed for privacy for her family.
“Jiwon continued to be hospitalised after collapsing, and she continued to have a hard time without ever being discharged,” one acquaintance wrote on social media.
The friend urged fellow runners to focus on honouring her memory and praying for her family instead of circulating unverified information.
Since then, tributes have poured onto Yoo’s social media accounts from club runners, engineers and athletics fans throughout South Korea.
