Stage 1 of the 2024 Tour de France saw the peloton take on blistering temperatures as the heat index reached 40ºC (104°F). And the riders didn’t have time to cool down on stage 2 either as the mercury hit upwards of 31ºC (88°F).

For our riders, adapting to race in these kinds of temperatures is not only a performance benefit, it’s also important for their health. It starts the moment they join our team. Our riders work closely with our performance and medical staff to ensure that they arrive at races in the best physiological shape.

“The best example is probably Ben Healy,” says EF Pro Cycling head doctor Jon Greenwell. “In Ben's first season, he went to one of the races in Belgium and it was 32, 33 degrees celsius, and he really struggled. The first two days were really hard for him and that's when we worked out that the heat wasn't very good for him.

“At our team camp in December, sport director Charly Wegelius gave us a heads up of who was likely to be on the long list for the Tour and said, ‘These ones we know potentially have a problem in the heat. Are they going to be able to do the Tour?’

"So again, using Ben as an example, we took Ben into the laboratory at Loughborough University, on either Boxing Day or the day after Boxing Day, and put him in the heat chamber and ran a test. We measured various parameters including how much sodium he lost in his sweat, how much weight he lost, how much fluid he lost, his body temperature, how uncomfortable he felt in that environment. We then sent him away, and for seven days he did our standard team heat acclimatization protocol, and then we took him back into the laboratory a week later, and then re-measured everything to see what the adaptation was.

"The test showed that he was able to acclimate to heat and it was actually quite helpful because we could really individualize the program for him and that's what we've been doing over the last six months is using the results of that to look at how we work with him.”

But how can you get better at riding in the heat? And what does a heat acclimatization actually look like? Here are five tips from Dr. Greenwell on how you can prepare for your next long ride or race in the summer heat.

There are two approaches to heat adaptation. One is to ride inside on a turbo trainer at intensity and without a fan to increase your core body temperature to at least 38.5˚C. This may include heating up the room in advance or wearing additional layers like arm warmers, a rain jackets, and a hat. Some riders will even wear a painter’s suit in order to really get sweating. Maintain this for about 45-75 minutes.

The other way is to take a hot bath, usually at 40˚C. Sitting in the bath will raise your core temperature, helping your body to adjust to the heat.

It is key to take on fluids during a heat adaptation session, but not cold fluids. Staying hydrated will help your body to continue to function while in the heat. It’s a common misconception that heat adaptation is about adjusting to dehydration, but dehydration can be dangerous in extreme temperatures. Continue to drink room temperature or even warm beverages throughout.

A lot of new research came off the back of the Tokyo Olympics, particularly from sports like cycling, triathlon, and athletics because of the concern about how athletes would respond to the high heat, high humidity environment. We’ve taken that research and adapted it. We do heat adaptation for two main reasons. It’s for performance gains, but it’s also for rider health. After completing a heat adaptation program, a rider is less likely to get heat stroke and is more likely to tolerate the heat better, meaning losing less sodium, being less dehydrated, and feeling better generally.

Sensors like the Nix Biosensors are incredibly useful to measure sodium loss rate, one of the key indicators of heat adaptation. As the body adjusts to heat, it loses less and less sodium. The Nix Biosensor allows you to measure how your body is maintaining or losing sodium, so you can get a better understanding of how you are acclimatizing to the heat. When you are adapting, you can expect to sweat more, and earlier, but with a lower sodium content. Ultimately, that is what heat adaptation seeks to achieve as it indicates your body is better able to cool itself. In the past, we needed to visit a lab to measure sodium loss but the Nix Biosensor allows us to collect this data right at home.

It’s important to continue to have methods to cool your body down, even once you are heat adapted. If you do get too hot, you want to cool down as quickly as possible. This can include pre-race, in-race, and post-race cooling. This may involve eating ice gels before or during the race. Easily digestible, ice gels have a texture similar to a slush puppy, and bring down the body’s core temperature, thereby lowering the heat stress and allowing you to race harder, for longer. You’ll see our riders pouring water bottles over their heads, backs, and legs in a race, but an alternative is to run your head under a water fountain, take a dip in a pool, or get into a cold or lukewarm shower.

Find out more about Nix Biosensors by heading here. 

Learn more about the Amacx Ice Gels we are using at this year’s Tour de France here.