A summer of record-breaking temperatures across Europe, Asia, Africa and North America has pushed heat stress to the forefront of concerns in elite sport, with experts warning that adaptation is no longer optional but essential for the survival of competitive athletics.
The scale of the problem has become increasingly visible. Tennis has seen players collapse mid-match, including Ekaterina Alexandrova in Memphis and Jakub Mensik in Paris. Cyclist Tom Pidcock described conditions at the Tour de France as resembling a "war zone." In football, referee Ilgiz Tantashev, who took charge of France's turbulent last-16 win over Paraguay, was later diagnosed with heat strain. Tragically, young Fijian rugby player Saimoni Vunilagi died of suspected heatstroke on 7 August in Fukuoka, Japan, after training in temperatures reaching 35C.
Alex Hutchinson, author of the acclaimed book "Endure: Mind, Body, and the Curiously Elastic Limits of Human Performance," says his perspective on heat has shifted dramatically since writing the book in the 2010s. "Here I am in Canada, a famously frosty country, and my general take when I wrote 'Endure' in the 2010s was that heat was not that big a deal," he said. "Now I'm a lot more cautious. My general thesis is that the brain is pretty good at protecting you... But heat is one of the very few things that can trick the brain's protective circuitry."
Dr Lee Taylor of Loughborough University, a leading expert in preparing athletes for extreme conditions, argues that adaptation is now unavoidable across all levels of sport. "The reality is that we live in a climate-change world," he said. "It's inevitable, whatever sport you play, at whatever level, that more of that training and playing is going to be in a hot environment. So either we stop playing sport altogether or we adapt."
Football's recent World Cup offered a glimpse of piecemeal adjustments — mandatory hydration breaks were introduced, though no additional measures applied even when the wet bulb globe temperature exceeded 32C, a recognized threshold for heat stress. Half-time extensions were generally not permitted, with the notable exception of the ceremonial appearance involving Ronaldo, Ronaldinho and Madonna before the final. Taylor noted there was "a clear rationale" for extending breaks in certain matches as a straightforward way to cool players and protect their safety, but commercial pressures ultimately prevailed.
One significant obstacle was the compressed acclimatisation window players had before the tournament, following a long domestic season. A similar issue affects amateur athletes, such as runners at the London Marathon, who can be caught off guard by unseasonably warm spring conditions after months of cooler training.
Despite the risks, Taylor suggests that proper heat preparation can become a competitive advantage. He pointed to the 2019 World Athletics Championships in Doha, where up to 40% of competitors failed to finish road races due to inadequate preparation. "Just by being prepared appropriately you've beaten nearly half the field," he said. His greater concern lies with athletes carrying undisclosed illnesses, viral infections, or medications, which can combine dangerously with heat exposure — particularly at events lacking proper medical infrastructure, including what specialists call a "heat deck" for rapid cooling in emergencies.
With the Premier League season beginning, Taylor believes the extreme summer heat may have inadvertently benefited clubs during pre-season training. He explained that roughly six weeks of heat exposure can increase an athlete's haemoglobin mass by 3-6%, an adaptation comparable to altitude training. However, he cautioned that maintaining training quality in such conditions is difficult, as heat increases fatigue and hampers recovery.
Perhaps most troubling, according to Taylor, is the growing unpredictability of extreme weather patterns, which undermines traditional preparation methods based on historical data. "We used to prepare for the worst possible outcome," he said. "But that's gone out the window over the last five years because we have these crazy outliers."
Based on reporting from Guardian Football.