Since the Tour began in Barcelona just over 10 days ago, the task facing riders has been even more arduous than they would expect at a Grand Tour.
As well as dragging themselves more than 3200km over mountain peaks and through buffeting headwinds, their bodies have had to battle with trying to keep cool.
“It takes an incredible amount of energy to cool the body because when it’s hot and the body temperature rises, it uses 70% of its energy to cool itself,” Pommerie said.
Heatstroke risk
During effort, a person’s body temperature can reach 39C, which would be considered a fever.
It is essential to cool some strategic parts of the body such as the neck, head, extremities and forearms.
Riders have gone through heat training to help themselves prepare for the extreme conditions of the Grande Boucle, but that can only do so much.
“You can do all the heat training that you want, but then when you are in the race … you have to face one week with really warm conditions. Every day it’s getting warmer and warmer, for sure. It’s a really difficult condition for the rider,” Mattia Michelusi, the head of performance at the Cofidis team, told AFP.
The first objective is to manage the fatigue provoked by heat.
“The guy who is unable to produce his watts, his power, gets to the finish rinsed,” TotalEnergies doctor Samuel Maraffi told AFP.
The second objective is to avoid getting heatstroke.
“It’s really an effort-induced heatstroke… you can get it even when it’s not hot,” Pommerie said.
Heatstroke can lead to feeling faint, going pale or even fainting.
“We want to avoid any kind of heatstroke that happens basically when the temperature is really high and the body is not able to dissipate this heat,” Michelusi said.
“The main strategy is to try to cool down the body as much as possible during the day.”
That involves using ice socks, cold water bottles and ice vests, either before, during or after each stage.
Some teams even provide special cooling mattresses for their riders to sleep on at night.
However, heat training sessions of 45 minutes to one hour cannot recreate the impact of riding for four to five hours in scorching heat.
“What happens is that they lose a big amount of water, and if you do that for several days in a row, it is almost impossible to replace the water that you lose,” Michelusi said.
And that increases the risks of getting heatstroke.
Infections risk
From Pommerie’s perspective, the teams are on top of the issue.
“They wet [the riders] a lot so that it evaporates with the wind, so they’ve largely got that under control,” she said.
“But that doesn’t change the fact that their bodies have suffered a lot.”
And the cumulative effect can harm a rider’s health.
The immense use of energy for cooling purposes can have “a huge impact on their digestive system” meaning they do not absorb what they eat as well as they would otherwise, Maraffi said.
He said it can also affect their sleep, which can lead to “a huge impact on their recovery” after a stage.
And just as when riding in cold temperatures, tiredness can make riders more susceptible to viruses.
“Under normal circumstances the immune system does not completely recover, so there is a susceptibility to infections, and the heat increases that,” Maraffi said.
– AFP