Published May 16, 2026 03:53AM
The first time I heard about heat training, I thought it was just another fad. We’ve seen countless products, ideas, and methods come and go from the world of cycling. But after nearly a decade of research, it’s clear that heat training is here to stay.
In the past few years, heat training has gone from a trendy experiment to must-have protocol. It’s easier to ask who in the WorldTour is not doing heat training, rather than who is. CORE is the leader of heat training — you can see its body temperature sensors attached to the heart rate monitors of professional cyclists — and it has teams of scientists dedicated to finding the next big thing.
It’s no secret that heat training can be boring. The typical protocol for an active heat training session involves riding at a steady output on an indoor trainer for 40-60 minutes. No intervals or specific drills, just pedaling away as the sweat pours off your body.
While not the most entertaining training, there is clearly something here. You can see Tadej Pogačar and Tom Pidcock wearing CORE sensors during races. In fact, there are entire teams dedicated to heat training. CORE officially partners with UAE Team Emirates-XRG, Lidl-Trek, Soudal Quick-Step, FDJ United – SUEZ, and many other professional teams.
We’ve already put together a complete guide to heat training, but in this article, we’re going to take it further. What is the next big thing in heat training? In a sport that is constantly pushing the boundaries of what’s possible, what is the next big innovation?
In preparing this article, I went straight to the top, and I was able to learn a few secrets about heat training that I didn’t know existed.
Does what you drink during heat training matter?
When I asked Aline Barre, endurance performance lead at CORE, if I should drink warm or cold water during heat training, I wasn’t expecting a very decisive answer. It was a “gym bro” kind of question, one that I had read in social media comments, with some riders claiming that drinking warm water improves the gains you make from heat training.
To my surprise, Barre said that yes, the temperature of the liquids you drink during heat training can have a significant effect on potential performance gains. You see, the purpose of heat training is to increase your body’s core temperature to the point where it starts working hard to cool itself back down. At a basic level, this is where the physiological adaptations occur.
If you are drinking cold water during heat training, you are actually helping cool down your body, possibly stunting some heat training gains. It’s like wearing an ice vest in a sauna – sure, you won’t suffer as much, but you also won’t get as many benefits from the heat of the sauna.
Instead of drinking cold water, Barre suggested drinking room temperature liquids to stay hydrated during heat training. Of course, you will lose more sweat than you can drink, but you still want to replace fluids during heat training. There is no evidence that intentional dehydration (i.e. not drinking) during heat training provides any additional benefits. Sip on room temp water instead.
What’s the connection between heat training and altitude?
Another heat training innovation is the combination of and relationship between heat training and altitude. At a physiological level, the effects are similar. Both can increase plasma volume, boost hemoglobin mass, and increase VO2 max in the range of four to six percent, said Ross Tucker, the CEO of CORE.
There are two key takeaways here: 1) Heat training can be used as a “substitute” for altitude training, and 2) heat training can be used before, during, and after altitude to maximize and extend performance gains.
The first takeaway often applies to amateur cyclists or those without the means to go to a three-week altitude camp. Pogačar can afford to train at Isola 2000 – the working father/mother of two cannot.
For the exact heat training protocol and training plan to follow, check out Cycling Heat Training: A Complete Guide.
The second takeaway is one that could be the next big thing in heat training. Professional cyclists are not only using heat training at altitude, they are also using it before and after. By completing a heat training block before altitude, cyclists have already started the physiological changes that occur at altitude (e.g. plasma volume, hemoglobin, etc.) This could potentially make it easier to transition to an altitude training block, rather than using the first 5-7 days to acclimate. Research is still needed to determine the exact timeline, but there could be something big here.
Cyclists are also doing heat training after an altitude camp to prolong the gains. Again, this all goes back to the physiological changes associated with altitude training, and how those effects are similar to those experienced through heat training. Performance gains from a typical altitude camp might last 3-4 weeks (as a hypothetical example). But if you did heat training immediately after an altitude camp, perhaps the gains would last twice as long.
Dr. Puck Alkemade of CORE says, “Haemoglobin adaptations acquired during an altitude camp return to baseline rather quick. Rønnestad 2025 has shown that three heat sessions/week can delay the return to baseline for Hbmass after an altitude camp.”
Imagine finding your peak form, the best legs of your life, but it only lasts for a few weeks. What if you could extend that peak to two months? These are the kind of performance innovations that CORE is chasing.
Secret research on sleep and recovery after heat training
You know you’ve stumbled onto something when CORE acknowledges an idea but doesn’t want to talk about it. Barre and I were discussing heat training, sleep, and the 24-hour recovery cycle. A few things were mentioned, such as hydration levels, round-the-clock monitoring, and cooling mattresses. But CORE wouldn’t say exactly what it is working on.
It was clear that Barre was excited about the research, so I wouldn’t be surprised if we see something in the future regarding sleep and recovery from heat training. We know that many teams already travel with individual mattresses designed for each rider. I always assumed this was about comfort and consistency. But maybe they have started using cooling mattresses, or a mattress that alternates between heating up and cooling down, almost like contrast therapy. Could you be making heat training gains in your sleep? Only time will tell.
What’s coming next in heat training?
CORE sees two major innovations in the future of heat training, one is already here while the other is an idea. First is individualization. Just like an eight-week training plan, you can’t just give the exact same plan to 10 different riders and expect them all to improve. Some riders need less stimulus, others more. Heat training certainly works, but you can only get the most out of it by making it unique to you.
This is where CORE’s technology comes in. Instead of just measuring temperature with a thermometer, CORE combines data from your skin temperature, heart rate, and heat flux to calculate a real-time heat strain score on a scale of one to 10. This pumps out an adaptation score over time, telling athletes and coaches how acclimated they actually are. Tucker admitted that there isn’t much data on the high end of that scale – Once you reach 100% heat acclimation, what’s next?
That is where individualization comes in. CORE’s 100% heat acclimation score is just a number, not a physical barrier. We know that heat acclimation improves performance, but what happens when you push past that?
Heat training works, there’s no doubt about that. Now the question becomes: What’s the best way to use it? Some riders do heat training year-round. Others will use it before, during, or after an altitude camp. A few riders will push past the 100% acclimation ceiling, while others find it better to target the minimum effective dosage. Like any tough training, heat training can help unlock a new level of performance. When paired with altitude, long-term use, and room temp fluids, you could find the best legs of your life.