Jonny Brownlee’s warning about racing in the heat: “my body has let me down since Cozumel”

With medals in three successive Olympic Games, Jonny Brownlee’s triathlon career stands alongside the best who have ever graced the sport. Yet the incident for which he’ll be more widely remembered – being helped across the line in the furnace of Cozumel by brother Alistair – was also a watershed moment.

Up to and including that 2016 season finale, Jonny had stood on a World Series podium 27 times in seven seasons. Following the collapse in Cozumel, the now 35-year-old placed top three just four times, all in cooler locations: Leeds, Stockholm, Edmonton and Sardinia in October.

The natural arc of an elite career? Maybe. But Brownlee was only 26 in Cozumel and he believes it left a legacy. “I’m doing a lot of investigation, but I think my body has let me down since Cozumel,” he explained at a recent event.

“When I go too far and get too hot I just blow up. I’ve struggled with that for years now, but I’m doing a lot of tests and a lot of heat training to see what I can do.”

While other athletes avoid transparency for fear of showing weakness, Brownlee has little wish to obfuscate. Now in the veteran stage of his career, he says he copes better in super short-distance racing before his body overheats – but his results at longer non-drafting formats have been poor in comparison.

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Brownlee’s bike coach Jacob Tipper is also keen to solve the puzzle, but he’s concerned about the environments triathletes are being asked to race in. “It’s a highly under-investigated area, but heat stroke caused by performance can be lethal,” he says. “And I’d argue triathlon is one of the few endurance sports where elite athletes are competing in extreme heat.

“Marathon running tends to be in the spring and autumn and even during the Tour de France, the most horrible days are at altitude and cooler.”

Tipper subscribes to the central governor theory – that our brains override our bodies when it gets too hot, forcing us to slow down. “It’s natural preservation. Certain individuals can get a strong self-preservation response where subconsciously the brain stops them being able to push themselves to the limit again.”

That’s a viewpoint Sam Shepherd, head of sports science at Precision Fuel & Hydration, shares. “There is evidence to suggest that the risk of exertional heat illness, and particularly exertional heat stroke, is elevated in athletes who have previously experienced it,” he says.

“A lot of the supporting evidence comes from research conducted by the military. Even 10 years ago, the National Athletic Trainers’ Association (NATA) stated that individuals with a history of exertional heat stress are at an increased future risk, particularly if they return to sport too quickly or fail to address the contributing factors – a lack of heat acclimation or poor hydration strategy.”

Shepherd also cites research showing individuals who’ve had one episode are four times more likely to suffer another – though he cautions it’s an unpredictable area.

“There are some suggestions that heat illness can damage central thermoregulatory pathways, and cause nervous system dysfunction which potentially attenuates the sweat response, therefore impairing the capacity for heat dissipation.”

Part of the problem for triathlon is its history. With Hawaii the pinnacle of the sport, it would take a brave individual to argue that conditions on the Big Island are too pernicious to race. On the contrary, it is embraced as part of the appeal.

Yet it has its victims. Britain’s Jodie Cunnama finished fourth in Kona in 2014 – sandwiched between a collapse in 2013 and heatstroke in 2015. “Ever since the heat stroke, every time my core temperature rises, my head begins to throb, and gets so bad I can’t lift it.”

It’s hardly controversial to say that the world’s best triathletes push themselves harder than most and increase their risk. But conditions are something race organisers, who have a duty of care, need to weigh up alongside hosting fees.

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