Players arriving in Miami for World Cup matches could face more than just opponents, as sweltering heat and humidity threaten to turn the tournament into a test of both endurance and skill.
Teams from cooler climates are at particular risk if they haven’t had time to acclimatize to Miami’s harsh conditions, warned Dr. Jason Kostrna, assistant professor and graduate program director of kinesiology at Florida International University. Kinesiology is the study of movement, exercise and physical performance.
“Unfortunately, it’s very humid here in Miami, so when you exercise, you start to sweat,” Kostrna said. Reuters.
«That means you don’t evaporate it. It just rolls off of you and you don’t get any heat loss.»
The physiological battle is intense. As players’ bodies struggle to cool down, their hearts work overtime to pump blood to the skin in a desperate attempt to release heat through evaporation – a process that fails in Miami’s sticky air.
“If that doesn’t work, it’s really trying to increase the heart rate,” Kostrna explains.
Kostrna said the heat stress adds to the already enormous pressure of representing your country, creating an additional burden that affects both physical performance and mental acuity.
«You’ll see that maybe the pace of the game drops a little bit, you’ll see that the decision-making becomes a little bit more conservative. Whether that’s conscious or unconscious depends on the athlete,» he added.
TEMPERATURE CLOSE TO 120 DEGREES FAHRENHEIT
Temperatures in the World Cup host cities are already a few degrees above the historical average.
Moreover, Kostrna painted a sobering picture when measuring the Wet Bulb Globe Temperature – in which, in addition to air temperature, air humidity, sunlight and wind speed also play a role.
“Our wet bulb temperature for some of these games could be close to 120 degrees Fahrenheit (48.8°C) when you factor in radiant heat, humidity, the ambient temperature and throw in a little bit of the plastic or concrete jungle effect,” he said.
“If we don’t actively work to take care of everyone, that’s enough to cause major heat illness.”
Heat mitigation measures have also been put in place for fans at Miami Stadium, where Miami-Dade County said it installed cooling stations, water trailers, hydration zones and misting areas for fans and employees during the tournament.
HYDRATION BREAKS A PLASTER SOLUTION
Although three-minute hydration breaks have been introduced for all matches to give players a chance to rehydrate, Kostrna suggested it is just a band-aid solution if they have not hydrated themselves in the days leading up to the match.
“If you’re behind on hydration, this isn’t going to magically fix it,” he said.
«For athletes, it can help get their heart rate down and get some hydration. (The hydration breaks) could be a little longer, that would probably be better.»
His advice for teams? Arrive early and acclimatize.
“My hope is that there aren’t any teams that really just come out of the plane and experience this for the first time,” Kostrna said.
«Hopefully they’ve been in town for weeks and they’ve been practicing in this (heat). That should be enough, even if you’re someone coming from one of these colder regions, your body will adapt over those weeks.»
Published on June 18, 2026
