When World Cup players take the field in Miami, they may find themselves fighting two opponents at once — the team across from them and the brutal South Florida heat.
Dr. Jason Kostrna, an assistant professor and graduate kinesiology program leader at Florida International University, is raising alarms about the dangerous combination of heat and humidity that could threaten player health and performance. Kinesiology is the scientific study of movement, exercise, and physical performance.
“Unfortunately here in Miami, it’s very humid and so when you go and exercise, you start dripping sweat,” Kostrna told Reuters. “That means that you are not evaporating it. It’s just rolling off you and you are not getting that heat loss.”
When the body can’t cool itself through sweat evaporation, the heart kicks into overdrive, pumping blood toward the skin in a last-ditch effort to shed heat — a process that largely fails in Miami’s thick, sticky air.
“Then when it can’t, it starts to really try and increase that heart rate,” Kostrna explained.
Beyond the physical toll, Kostrna noted that heat stress piles on top of the mental pressure players already feel when representing their country on the world stage.
“You’ll start to see the pace of play maybe drop a little, you’ll start seeing that decision-making becomes a little more conservative. Whether that’s consciously or unconsciously, depends on the athlete,” he said.
Temperatures Could Approach 120 Degrees Fahrenheit
Temperatures across World Cup host cities are already running several degrees above their historical norms. But when measured using the Wet Bulb Globe Temperature — a scale that accounts for humidity, sunlight, and wind speed in addition to air temperature — the numbers become even more alarming.
“Our wet bulb globe temperature for some of these games could be close to 120 degrees Fahrenheit (48.8°C) when you factor in radiative heat, humidity, the ambient temperature and throw in a little bit of the plastic or concrete jungle effect,” Kostrna said. “If we do not actively work to take care of everybody, that is enough to cause major heat illness.”
Miami-Dade County has announced that Miami Stadium will have cooling stations, water trailers, hydration zones, and misting areas set up for fans and workers throughout the tournament.
Hydration Breaks Only Go So Far
Three-minute hydration breaks have been added to all matches, giving players a chance to take in fluids during games. But Kostrna cautioned that those breaks won’t solve the problem if players haven’t been properly hydrating in the days leading up to a match.
“If you’re behind on hydration, this is not magically going to fix it,” he said. “For the athletes, it can help bring their heart rate down, get some hydration. (The hydration breaks) can be a little bit longer, that would probably be better.”
His strongest recommendation for competing teams is simple: get to Miami early and let your body adjust.
“My hope is that there are not any teams that are truly just showing up off the plane and they’re experiencing this for the first time,” Kostrna said. “Hopefully they have been in town for weeks and have been practising in this (heat). That should be enough even if you are somebody who is coming from one of these colder regions, your body will adapt over those weeks.”
