The images are becoming more frequent and more difficult to ignore: sweating footballers struggling under the searing heat of the FIFA World Cup; Wimbledon spectators wilting in record temperatures; and Tour de France riders climbing off their bikes and straight into what looks more like a mobile intensive care ward than a team bus.
As climate change drives more frequent and intense heatwaves, elite sport is confronting questions that extend beyond on-field performance. How hot is simply too hot to compete? And what will the ultimate cost of performing in extreme heat be?
“Eventually, people will start dying at these,” says body heat researcher Nic Daniels. “Hopefully it doesn’t come to that, to be the catalyst to make these changes.”
High Performance Sport New Zealand’s Head of Performance Physiology, Caroline MacManus, says it’s difficult when commercial reasons combined with extreme weather dictate an athlete’s performance.
“When you support individuals that you watch day in, day out work towards these goals, it’s incredibly frustrating. I felt at times when we were preparing, particularly for Tokyo, that everything we were doing was to make sure that they could actually compete in that heat and humidity.
“Yes, we were training the way we knew we had to. But we knew if we didn’t work towards keeping them cool, pre-cooling strategies, altering warm-up strategies, we knew they wouldn’t be able to perform. The human body just can’t. You put it in certain conditions and it just can’t.
“But I find it incredibly frustrating because I feel we’re putting people at risk and our jobs now are to make sure that we are keeping them safe while they try to perform at their very best.”
She says history is already littered with warning signs, pointing to British triathlete Jonny Brownlee’s collapse near the finish line at a World Series event.
“He comes into the last hundred metres of the World Triathlon Final and just falls apart,” she tells The Detail. “His brother had to pick him up and bring him over the line.”
She also recalls Callum Hawkins at the 2018 Commonwealth Games: “It just got too hot. His intensity was too high and he also fell apart and was lucky to be alive at the end of it.”
She says while elite athletes constantly push their physical limits, recreational athletes may actually be at even greater risk, but points out modern sport is adapting.
Water breaks have become commonplace in football, and marathons are increasingly shifted to dawn starts, while ice baths, cooling vests, electrolyte replacement and pre-cooling strategies have also become as important as fitness training itself.
MacManus says scheduling competitions around the heat is becoming unavoidable.
“Time of day is a huge one … You’ll see more and more of the marathons in the pinnacle events being moved to six, seven am starts for that very reason.
“I think one of the World Championships marathons was moved to something like one in the morning … We’re putting times of competitions in the middle of the night.”
Former Black Sticks goalkeeper and Olympian Bianca Russell knows exactly what competing in extreme heat feels like.
One of her earliest lessons came the hard way.
“Rookie mistake, it was so hot and humid … we started stripping off layers underneath all the goalkeeping gear that we would wear,” she tells The Detail. “And straight away I got … a skin abrasion on my shins.”
What seemed minor quickly became serious.
“It didn’t take very long being in the tropics for that to get horribly infected … We had to peel horrible skins and things off every few hours until we got rid of this infection. It was just horrific.”
The heat itself could also become dangerous.
Russell recalls a tournament in Argentina where temperatures climbed beyond 40 degrees.
“Three out of the four goalkeepers involved in those two games ended up needing medical attention for heat stroke or heat exhaustion.”
Following another match played in more than 40-degree heat in the Netherlands, players were forced to evacuate the stadium because of an approaching electrical storm.
“Two days later against Korea, I felt okay, but my feet would not move … It’s like you’ve got a residual effect from playing that hot game and you haven’t recovered.”
But she says today’s athletes have access to far more sophisticated cooling techniques than previous generations.
“Tour de France is a classic right now … some of the post-race care that those athletes are having is basically hospital care in their tour bus to get them hydrated, to get fluids back into their muscles and salts back into their muscles.”
But no amount of preparation can remove the limits of human physiology.
MacManus says sporting organisations increasingly rely on wet-bulb temperature – a measure combining heat and humidity – to determine when competition becomes unsafe.
“Theoretical limit is about 35 degrees on this wet-bulb temperature.
“[But] practical healthy limits … we’re probably looking at about 30 degrees to 31 degrees.”
The challenge becomes even greater during exercise.
“The body just says no.”
Body heat researcher Nic Daniels, a PhD student at the School of Physical Education, Sport and Exercise Science at Otago University, says many people assume the danger comes solely from the weather.
In reality, much of the heat comes from within.
“We’re producing heat constantly and we have to get rid of that heat. If you start doing higher levels of activity, you produce more and more heat … the environment then limits how much we can get rid of the heat.”
That means the harder an athlete pushes, the lower the safe environmental limit becomes.
“As you start exercising and as you exercise harder and harder, those critical limits will come lower and lower and lower. So the level of activity you can do is reduced the hotter it is.”
Importantly, Daniels says athletes are not the only people at risk.
“Athletes are really good at getting rid of heat … equally a huge worry is on people working in that kind of heat.”
Ground crews, volunteers, security staff and even spectators may face similar, or greater, danger.
“They might not be producing as much heat, but they’re arguably probably less fit than the athletes that are competing. So their level of risk could potentially be just as high.”
As temperatures continue to rise globally, questions are growing over whether major sporting events themselves will need to fundamentally change.
MacManus believes they will.
“Things will have to change … at some point, the human response to performing in the heat, there will be a limit to it.”
She hopes sport doesn’t wait for tragedy before acting, while Daniels says the conversation shouldn’t stop at protecting athletes.
“We should also flip the question: so what are the effects of these events on climate change?
“Whether we even have them in the first place, like how valuable they are to our society, should be questions we’re asking.”
Check out how to listen to and follow The Detail here.
You can also stay up-to-date by liking us on Facebook or following us on Twitter.
