'You can die from heatstroke': XDS Astana doctor issues stark Tour de France warning after Elisa Longo Borghini suffers severe heat illness

Elisa Longo Borghini began the final stage of the Tour de Suisse just ten seconds behind race leader Marlen Reusser. Overall victory was still possible.

By the finish, she had lost 9 minutes and 56 seconds. More concerning was the fact that she could barely remember the final climb.

The Italian recalled taking supplies from her coach, but little else. Her symptoms were consistent with heat illness, a condition that can quickly become life threatening when the body is no longer able to control its temperature. Post race, Longo Borghini confirmed to social media that she had suffered from heat stroke on the final stage.

“Heat stroke is an extremely serious medical emergency,” said Dr Emilio Magni, medical director of XDS Astana to bici.pro. “It occurs after prolonged exposure to very high temperatures and humidity. The body reaches a point where it can no longer release the heat it is absorbing.”

The danger is becoming harder for professional cycling to ignore. Riders regularly compete under intense sunlight and in humid conditions, often during the hottest hours of the day.

At the Italian women’s road championship in Pordenone, the race was scheduled to start at 1pm. At the same time the previous day, the temperature had reached 37 degrees Celsius.

“We have to accept that climate change is no longer just something people talk about,” Magni says. “It is a reality, and sporting events have to respond. There are protocols for extreme weather, but in some places extreme conditions are becoming normal.”

With large parts of Europe experiencing unusually high temperatures and the Tour de France approaching, those protocols could soon become highly relevant. 

The UCI assesses heat stress using the Wet Bulb Globe Temperature index, which considers not only air temperature but also humidity, direct sunlight and wind. The speed of the peloton can also be taken into account because airflow helps cool riders while they are moving.

Under the UCI’s High Temperature Protocol, officials can introduce additional drinks, ice and shaded waiting areas when the risk increases. In the most dangerous conditions, they can change the start or finish time, shorten or neutralise part of a stage, or cancel it altogether.

During exercise, the body produces heat and attempts to release it through sweating and increased blood flow to the skin. High humidity can make that process less effective.

“The temperature regulation systems in the brain begin to fail,” Magni explains. “Then cardiac activity, circulation and the dilation of blood vessels are affected. It is like a short circuit.”

Muscular performance also deteriorates as body temperature rises.

“The enzymes involved in muscle contraction work best at around 37 degrees,” he says. “When the body reaches 40 degrees, you may no longer be able to pedal properly.”

Early signs can include headache, nausea, confusion and poor coordination. The problem is that riders are trained to tolerate pain and continue racing.

“Cyclists are a particular kind of animal,” Magni says. “During a race, they think only about going fast. When they crash, their first instinct is to get back on the bike.”

That mentality can become dangerous when heat starts to affect judgement. By the time a rider realises something is seriously wrong, they may no longer be capable of making a rational decision.

Ice vests, cold drinks and ice placed inside jerseys are now common at hot races. Teams also focus on hydration and lighter meals before the start.

“The first priority is intensive hydration,” Magni says. “You need to give the body enough fluid reserves. Food should also be light, because you do not want digestion placing another burden on the body.”

These measures may delay overheating, but they cannot eliminate the risk.

“They are temporary solutions,” he warns. “When heatstroke is suspected, the person must be moved into a cool environment and their temperature must be brought down as quickly as possible.”

That raises a wider question for cycling. Should races still begin in the early afternoon when extreme temperatures are forecast?

The heat cost Longo Borghini any chance of winning the Tour de Suisse. But as Magni warns, the consequences can go far beyond losing time.

“You can lose a race because of the heat,” Magni says. “But you can even die from heatstroke.”