# Death of Yoo Ji-won during Seoul half-marathon

> Live situation record from CLSTR: https://clstr.news/situations/death-of-yoo-ji-won-during-seoul-half-marathon
> Updated: 2026-10-20T07:45:19.000Z. Sources: 23. Developments: 3.

Yoo Ji-won, a 25-year-old running influencer and KAIST graduate student researching AI semiconductors, passed away after collapsing during the 2026 Seoul Race half-marathon on October 11. The collapse occurred at approximately 8:49 a.m. near the 20.6 km mark, roughly 500 meters from the finish line.

Emergency responders provided on-site first aid and CPR before transporting her to a medical facility, but she could not be revived. While the official cause of death has not been formally disclosed, medical experts noted that sudden cardiac death in athletes under 35 is often linked to underlying structural heart issues. The incident has prompted discussions regarding the risks of endurance exercise, such as sudden cardiac arrest or heatstroke, even among fit individuals.

Yoo was a prominent figure in the amateur running community, recognized for high-level performance including a ‘Sub-3’ marathon finish and a 10km race victory in April. The Seoul Race Organizing Committee confirmed the tragedy, expressed condolences to her family, and announced a thorough investigation into the incident.

Following her death, a debate has emerged within the South Korean running community regarding “memorial runs.” Some runners have shared workout logs on social media as tributes, with some posts stating, “Yoo Ji-won, we’ll run the remaining 500 meters for you.” Critics argue that using a tragedy to showcase personal fitness milestones may be inappropriate and could distress the family, while supporters maintain these activities are sincere ways to honor her memory.

## Timeline

### 2026-10-20: South Korean runners spark debate over memorial runs

Social media posts by runners sharing workout records to honor Yoo Ji-won, a student who died during a Seoul marathon, have sparked debate over the appropriateness of such tributes.

2 sources. https://clstr.news/cluster/south-korean-runners-spark-debate-over-memorial-runs

### 2026-10-15: Yoo Ji-won, South Korean running influencer, dies during Seoul half-marathon

South Korean running influencer and KAIST graduate student Yoo Ji-won, 25, died after collapsing 500 meters from the finish line during the Seoul Race half-marathon on October 11.

10 sources. https://clstr.news/cluster/yoo-ji-won-south-korean-running-influencer-dies-after-marathon-collapse

### 2026-10-13: Yoo Ji-won dies after collapsing during Seoul Race half-marathon

Running influencer and KAIST researcher Yoo Ji-won, 25, died after collapsing 500 meters from the finish line during the 2026 Seoul Race half-marathon.

11 sources. https://clstr.news/cluster/runner-and-influencer-yu-ji-won-dies-during-seoul-race-half-marathon

---
Cite as: Death of Yoo Ji-won during Seoul half-marathon. CLSTR, https://clstr.news/situations/death-of-yoo-ji-won-during-seoul-half-marathon