Tour de France: with heat training, the peloton heats up

With his head and legs wrapped in plastic and his winter clothes on, Norwegian Tobias Johannessen rides under a bright sun and a pleasant temperature of 25 degrees Celsius. At first glance, this video, which the Uno-X Mobility rider posted on his Instagram account a few days before the start of the Tour de France, makes no sense.

But actually it is: it's part of her heat training, designed to raise her body temperature to 39.6 degrees.

"Of course, the main benefit is adapting to perform in the heat," Nordic team doctor Rory Nolan told AFP. "It can have a real impact on how the body manages energy."

Acclimatizing to the heat becomes even more important as the climate warms and stages run in temperatures above 30 degrees become almost the norm in the Tour de France.

But that's not the only goal of heat training , which is now practiced by almost all teams. It also promotes an increase in blood plasma volume, which helps the heart transport oxygen more efficiently to the muscles, a key factor in performance in this demanding sport.

“The normal response to heat is for blood vessels to dilate a little less on the surface, which increases blood flow to the muscles and helps performance during the stages,” explains Rory Nolan.

"Significant development"

Heat training thus offers similar benefits to the altitude training that teams have been practicing for many years.

The UAE team maintains that Tadej Pogacar's progress since 2024, particularly visible during the last Tour de France, is partly attributable to the development of this "heat training."

"This is an important development that we have implemented effectively," emphasizes Jeroen Swart, his team's performance director.

"The advantage of this protocol is that it can be done from anywhere, so essentially from home, whether in hot baths or on a home trainer (an indoor bike, editor's note) with clothes on," emphasizes David Hulse, a member of the EF Education-EasyPost medical team.

This makes it easy to adapt the protocol to each runner, as some come from hot countries and react better to high temperatures.

"During our training camps, doctors will analyze how each rider reacts to the heat to determine how long they should stay in a hot bath or on the bike," adds David Hulse.

"There are constraints"

The US team implemented this training after the 2021 Tokyo Olympics, benefiting from the experience of their medical team leader, Jon Greenwell, who was then monitoring the British triathlon team as they battled through the intense heat of the Japanese summer.

This training was particularly useful for EF Education rider Ben Healy, winner of the 6th stage last Thursday, who grew up near Birmingham, England, where the mercury rarely goes crazy.

"He was one of the first riders on the team to follow this program, and it helped him a lot for last year's Tour," says David Hulse.

These exercises are all the more useful to Uno-X, whose Tour squad is composed exclusively of Norwegian riders, who sometimes train "in -10°C temperatures," according to Rory Nolan. The team implements heat training "all year round, and more so at the start of summer, so before the Dauphiné and up until the Tour," he reveals.

But not all riders are keen on this new method: "I'm a bit old-school," jokes Decathlon-AG2R rider Bruno Armirail. "But today, everyone does it, and (...) since you have to perform well, improve, you have to do it. It's our job, being a cyclist, there are constraints."