Heat and Humidity Put More Than One-Third of World Cup Matches at Risk

More than one in three matches at the ongoing men's World Cup are at risk for dangerously hot and humid conditions, according to an analysis by NPR. The tournament, hosted across stadiums in the United States, Canada and Mexico, runs through July 19 and coincides with peak summer temperatures.

One of the primary steps recommended to prevent heat illness is frequent water intake. U.S. and Canada are permitted to bring one factory-sealed disposable water bottle into stadiums, while attendees at venues in Mexico must purchase water inside. Alcohol consumption increases dehydration risk and reduces awareness of heat illness symptoms.

Workers and fans engaged in physical activity should prioritize water over other beverages, heat researcher Jennifer Vanos of Arizona State University said.

Shade reduces heat exposure compared with direct sunlight. Spectators can use umbrellas, hats and loose-fitting clothing, while workers should be given regular water and shade breaks under Occupational Safety and Health Administration guidance. Lines for transportation or entry can present particular hazards because shade is limited in crowds.

Trees provide cooler conditions than open areas exposed to sun, Vanos said.

Heat exhaustion can lead to heat stroke if untreated. Common symptoms include thirst, headache, nausea, dizziness, weakness and decreased urine output, according to Centers for Disease Control and Prevention guidance. Stadiums facing hot weather maintain cooling stations, medical stations and fans.

First Aid locations appear on interactive maps on FIFA's website. Anyone experiencing severe symptoms should call 911, the CDC recommends.