During a marathon event in Seoul, South Korea, on October 20, 2024, at least 12 runners collapsed due to heat-related illnesses, prompting emergency medical responses and raising concerns about participant safety in endurance events during extreme weather.
The incident occurred during the Seoul International Marathon, held under unusually high temperatures for late October, with ambient conditions reaching 28°C (82°F) and high humidity levels. Medical personnel from the Seoul Fire Department reported that multiple participants exhibited symptoms of heat exhaustion and heat stroke, including dizziness, nausea, profuse sweating followed by sudden cessation of sweating, confusion, and loss of consciousness.
According to officials from the Seoul Metropolitan Fire and Disaster Headquarters, emergency responders treated 12 individuals on-site, with seven requiring hospitalization for further evaluation and treatment. All hospitalized runners were reported to be in stable condition by the following day, with no fatalities recorded.
“In hot weather, prolonged intense exercise like marathon running causes rapid loss of fluids and electrolytes through sweat, impairing the body’s ability to regulate temperature,” said a spokesperson for the Seoul Fire Department during a press briefing on October 21. “When sweating suddenly stops, it’s a critical warning sign that the body is overheating and may be entering heat stroke.”
The event organizers, the Seoul Metropolitan Government and the Korea Association of Athletics Federations, confirmed that medical stations were positioned every 2 kilometers along the 42.195-kilometer course, equipped with ice baths, oral rehydration solutions, and intravenous fluid administration capabilities. Despite these precautions, the cumulative effect of sustained exertion in warm conditions overwhelmed some participants’ thermoregulatory systems.
Heat-related illness during endurance events remains a significant concern in sports medicine. The Koreans Centers for Disease Control and Prevention (KCDC) notes that exertional heat stroke—a life-threatening condition characterized by a core body temperature above 40°C (104°F) and central nervous system dysfunction—is a leading cause of preventable death in athletes, particularly in humid environments where sweat evaporation is limited.
“The body’s primary cooling mechanism is evaporation of sweat,” explained Dr. Min-joo Lee, a sports medicine physician at Asan Medical Center in Seoul, in an interview with Yonhap News Agency on October 22. “When humidity is high, sweat doesn’t evaporate efficiently, so heat builds up internally. Even well-trained athletes can succumb if fluid and electrolyte replacement doesn’t match losses.”
Medical experts emphasize that prevention strategies include pre-event hydration, acclimatization to warm conditions, pacing adjustments based on real-time weather feedback, and immediate recognition of early symptoms such as headache, cramping, and excessive fatigue. The American College of Sports Medicine recommends that event organizers implement wet-bulb globe temperature (WBGT) monitoring to assess environmental risk and modify or cancel events when thresholds exceed safe levels for physical activity.
In response to the incident, the Seoul Metropolitan Government announced a review of its marathon safety protocols, including potential adjustments to start times to avoid peak daytime heat, enhanced participant education on heat illness prevention, and expanded medical staffing at future events. No changes have been made to the scheduled date of the 2025 Seoul International Marathon, which remains set for March 2025, when temperatures are typically cooler.
This incident adds to a growing global pattern of heat-related medical emergencies in mass participation races. Similar occurrences have been documented in recent years at marathons in Paris, Tokyo, and New York City, where unseasonably warm weather challenged traditional seasonal expectations for endurance events.
As climate patterns shift and extreme heat events become more frequent, sports governing bodies worldwide are reevaluating race scheduling, course design, and safety standards. World Athletics, the international governing body for track and field, updated its environmental guidelines in 2023 to recommend that marathons be held when the WBGT index is below 28°C to reduce health risks.
For participants preparing for future marathons in warm climates, health authorities advise gradual heat acclimatization over 10–14 days, monitoring urine color as a hydration indicator, consuming electrolytes during prolonged exertion, and avoiding nonsteroidal anti-inflammatory drugs (NSAIDs) before racing, which can impair kidney function under dehydrated conditions.
The Seoul Fire Department continues to urge runners to listen to their bodies and seek medical assistance at the first sign of distress, emphasizing that finishing a race is never worth risking long-term health or life.
Official updates on marathon safety guidelines and event approvals are posted regularly by the Seoul Metropolitan Government’s Sports Affairs Division. Readers are encouraged to consult these sources for the most current information on participant safety standards in South Korea.
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