Using Heat to Extend Altitude Benefits for the Tour de France with Lidl-Trek

Back to the basics of heat training and heat adaptation. Coaches typically distinguish between short-term and long-term heat adaptation: 

Lidl-Trek has implemented a hybrid heat-altitude strategy that leverages the synergy between the two environments: 

“Leading up to the altitude camp, we did blocks of specific heat training so it wasn’t a total shock to the system to be exposed to both heat and altitude at the same time,” Coach Mattias Reck explains. 

Their camp in Sierra Nevada in May brought natural heat exposure due to the time of year. With the CORE sensor, coaches could monitor that riders were accumulating sufficient heat strain during regular training sessions, which minimized the need for additional structured heat protocols during the camp. But as the Tour de France starts weeks after that altitude block, maintaining those adaptations became critical. 

“Since the altitude camp came quite far from the Tour, we used heat training between the Dauphiné and the Tour to preserve the altitude effect,” says Coach Mattias Reck. 

This decision proved especially valuable for sprinters and support riders, who stayed at sea level to train for high-speed efforts, while still holding onto the altitude-induced performance gains. 

“Instead of doing another short altitude camp like the GC guys, we maintained those benefits with heat, while fine-tuning sprint performance.” 

Research backs this approach. In a 2024 study by Oberholzer et al., cyclists completed a 3-week altitude camp followed by 3.5 weeks of sea-level training. The control group lost 71% of the +4.1% hemoglobin mass it had accrued at altitude. In contrast, the group that conducted 3 heat training sessions per week after returning to sea-level had maintained all its hemoglobin mass gains. 

But that’s not all. The study also found an 8% plasma volume decrease after 3 weeks of altitude training, indicating that athletes who compete in a hot climate too soon after returning from altitude are less heat adapted because of the lower plasma volume.

The lead researcher of the study, Daniele Cardinale (pictured above), explains, 

"I would not recommend competing in a hot climate shortly after an altitude camp without a proper heat acclimatization phase beforehand. Heat acclimatization is multifaceted and involves more than just an increase in plasma volume. However, in our study, during the 3.5 weeks at sea level the HEAT group displayed a numerically larger increase in plasma volume from post-altitude than the control group (12% vs. 6%, respectively). Therefore, it could be speculated that the larger increase in blood volume following HEAT during the 3.5-week maintenance period could be beneficial for the athlete by increasing the stroke volume and thus, the maximal cardiac output, via the Frank-Starling mechanism – as well as better thermoregulation during prolonged exercise.”

Heat is a powerful lever for teams aiming to hold their gains without repeating altitude cycles close to race day, and when used strategically can balance out the physiological costs of altitude training.

You don’t need a two-week camp in the mountains to increase your hemoglobin mass. Done right, heat training can be a powerful standalone, or maintenance stimulus. Here’s how:

Build-Up Phase (10–14 heat sessions over 2–3 weeks)

- Goal: 40–50 min in CORE’s Heat Zone 3 
- Clothing: overdressed (thermal + waterproof layers) 
- Start the workout by ramping intensity – 3×5 min at 80/90/100% FTP to elevate core temp   
- Once in Heat Zone 3, reduce power. Due to the insulation layers, your core temp will stay elevated. Aim for a Heat Strain Index of 3.0–6.9. 
- Stay hydrated: Measure your sweat loss, and drink before, during, and after the heat session. 
-Frequency: 3–6 sessions/week   

Now your body is short-term heat adapted and ready to race in hot conditions. Make your last heat session 3–5 days before race day.

Maintenance Phase (until race day)

- 1h Z2 ride, overdressed 
- No need for high intensity  
- Usually leads to 20–30 min in Heat Zone 3  
- Frequency: 3–4 sessions/week     

Keep your Heat Adaptation Score above 80% for at least 3 weeks to get hemoglobin gains.

In the final weeks before the Tour, sprinters, domestiques, and even GC riders can benefit from targeted heat blocks to extend the physiological “tail” of altitude training without the travel, cost, and training compromise of another high-altitude block. 

After five hours in the saddle, the heat-trained riders will have the edge — whether it’s a summit finish or a chaotic sprint. 

Heat training is no longer the "poor man’s" altitude. It’s the best-kept strategy to extend altitude benefits, enhance thermoregulation, and sustain performance under fatigue, where races are won or lost.  

Whether you’re chasing yellow or chasing the breakaway, one thing is clear: 

Altitude builds the engine. Heat keeps it firing.