Heat training is one of the most powerful — and most misunderstood — performance tools available to amateur cyclists. Done right, a 10-14 day heat acclimation protocol can increase your plasma volume, improve your cardiovascular efficiency, and add measurable watts to your FTP. The research shows gains of 5-8%, and those gains hold even when you race in cool conditions.
When Dan Lorang came on the Roadman Cycling Podcast and walked us through exactly how he heat-acclimates his Grand Tour riders before major stage races, it confirmed what the research has been saying for years. This isn't a niche tactic for desert stage races. It's a genuine performance multiplier — and you can do it at home on your indoor trainer with a space heater and some extra layers.
In this guide:
- Why heat training works
- The science of heat acclimation
- The at-home heat training protocol
- Heat training for performance gains
- Safety considerations for masters riders
- How long does heat acclimation last?
- What the experts say
- Frequently asked questions
Why Heat Training Works
Here's the thing nobody tells you about heat training: it's not really about surviving hot races. That's a bonus. The real reason World Tour coaches prescribe heat blocks is because the physiological adaptations transfer directly to performance in any conditions.
When you train in heat, your body is forced to solve a problem — it needs to cool itself while still delivering oxygen to working muscles. That dual demand triggers a cascade of adaptations that make you a more efficient cyclist, full stop. Your heart gets better at pumping blood. Your blood volume increases. Your body learns to cool itself earlier and more effectively.
Dan Lorang doesn't heat-train his riders because he's worried about one hot stage. He does it because the adaptations — more plasma volume, better cardiac output, improved thermoregulation — make them better on any day, at any temperature.
→ Read the full guide: Heat Training for Cyclists: The Complete Guide
The Science of Heat Acclimation
Let me break this down. When you repeatedly exercise in hot conditions, your body makes five specific adaptations:
| Adaptation | What Happens | Why It Matters |
|---|---|---|
| Increased plasma volume | Blood volume expands by 5-12% | More blood per heartbeat means lower heart rate at the same power |
| Improved sweat rate | You start sweating earlier and more efficiently | Better cooling means less cardiovascular strain |
| Lower resting core temperature | Baseline temperature drops | You have more headroom before overheating |
| Reduced heart rate at submaximal effort | Heart works less hard at the same wattage | Direct efficiency gain — same power, less cardiac cost |
| Improved cardiovascular efficiency | Better cardiac output and stroke volume | The engine gets bigger |
The first three adaptations appear within 5-7 days. Full acclimation — all five firing — takes 10-14 days of consistent heat exposure. That's not months of work. That's less than two weeks for a meaningful performance boost.
Here's where it gets really interesting: the plasma volume expansion alone improves your body's ability to deliver oxygen to working muscles. More blood volume means more oxygen transport per heartbeat. That's essentially the same mechanism behind altitude training — but you can do it in your spare room.
→ Read the full guide: Heat Training Protocol at Home for Cyclists
The At-Home Heat Training Protocol
You don't need a climate chamber. You need an indoor trainer, a warm room, and a plan.
The setup:
- Close the windows. Turn off the fans. If you have a space heater, point it at yourself. The goal is an ambient temperature of 30-35°C (86-95°F).
- Wear an extra base layer or a light jacket. This raises your microclimate temperature further.
- Have fluids within reach — at least 500ml per hour with electrolytes.
The protocol:
| Day | Duration | Intensity | Notes |
|---|---|---|---|
| Days 1-3 | 45-60 min | Zone 2 (easy) | Your body is adjusting. Heart rate will be higher than normal. That's expected. |
| Days 4-7 | 60-75 min | Zone 2 | You'll notice heart rate starting to normalise. Sweat rate increases. |
| Days 8-10 | 60-90 min | Zone 2, with 2-3 short tempo efforts | Begin introducing some intensity as your body adapts. |
| Days 11-14 | 60-90 min | Zone 2 base with threshold intervals | Full protocol — your body is now acclimating efficiently. |
The critical rules:
- Keep the intensity predominantly Zone 2. This is not the time for VO2max intervals in a sauna.
- Weigh yourself before and after every session. Drink to replace what you've lost. If you're losing more than 2-3% of body weight per session, you're under-hydrating.
- Monitor your heart rate. If it's more than 15-20 bpm above your normal Zone 2 heart rate and won't settle, cut the session short.
- Stop immediately if you feel dizzy, nauseous, or confused. Heat illness is serious.
→ Read the full guide: Heat Training on an Indoor Trainer: The Complete Protocol
Heat Training for Performance Gains
The performance numbers are real. Studies show FTP improvements of 5-8% from heat training alone — and those are averages. Some riders report gains of up to 30 watts when they combine heat acclimation with their existing structured training.
Let me be really clear about this: those gains don't come FROM the heat sessions. The heat sessions trigger adaptations — more plasma volume, better cardiovascular efficiency — that allow your body to produce and sustain higher power across all conditions. You're not training harder. You're training your body to be more efficient at delivering oxygen to your muscles.
The biggest misconception is that heat training only helps when it's hot. The plasma volume expansion, the improved cardiac output, the better thermoregulation — all of those benefit you whether you're racing in 35°C in Mallorca or 12°C in Belgium. The body doesn't care why it adapted. It just adapted.
This is precisely what Dan Lorang was describing on the podcast — how the team's heat protocol before the Vuelta produced gains that carried into later season performances regardless of temperature.
→ Read the full guide: Heat Training for Cyclists: How to Gain Up to 30 Watts FTP
Safety Considerations — Especially for Masters Riders
Let me be really clear about this: heat training carries genuine risks. This is not something to approach casually. Heatstroke is a medical emergency, and every year cyclists end up in hospital because they pushed too hard in conditions their body wasn't ready for.
For all riders:
- Never train in heat without fluids immediately available
- Always have someone who knows where you are
- Stop the session if you feel dizzy, nauseous, have a headache, or your skin stops sweating (a danger sign)
- Build up gradually — start with shorter sessions and extend over days
- Avoid heat sessions when you're already fatigued, dehydrated, or ill
For masters riders (40+), the risks are higher:
- Heat tolerance decreases with age. Your thermoregulation system becomes less responsive. Your sweat response slows. Your cardiovascular system has less reserve.
- Start with even shorter sessions (30-40 minutes) and build more gradually
- Consider a heart rate ceiling — if you're consistently 20+ bpm above normal, the session is too stressful
- Talk to your GP before starting a heat protocol if you have any cardiovascular history
- The gains are still available to you, but the margin for error is smaller. Respect that.
The good news is that with sensible progression, heat training is safe and effective for riders of all ages. It just requires more caution and a slower ramp for older athletes.
→ Read the full guide: Heat Tolerance and the Ageing Cyclist
How Long Does Heat Acclimation Last?
This is one of the most common questions we get in the Not Done Yet community, and the answer matters for timing your protocol around target events.
| Timeline | What's Happening |
|---|---|
| Days 1-5 | Initial adaptations begin — plasma volume starts increasing, heart rate at same effort begins to drop |
| Days 5-7 | Sweat rate improvements, early thermoregulation gains |
| Days 10-14 | Full acclimation — all five adaptations in place |
| After 2-3 weeks without heat exposure | Benefits start to decay — plasma volume contracts first |
| After 4-6 weeks without heat exposure | Most acute adaptations lost, though some residual benefit remains |
The practical takeaway: Time your heat block to finish 3-7 days before your target event. That gives you full acclimation benefits plus a few days of recovery from the training stress. If your event is in six weeks, a heat block now will have mostly decayed by race day.
Some coaches — and Dan Lorang is one of them — recommend maintenance doses: one or two heat sessions per week after the initial block to maintain adaptations without the full training load. It's a smart approach if you're trying to hold the gains across a longer period.
What the Experts Say
The insights behind this guide come from direct conversations on the Roadman Cycling Podcast:
Dan Lorang (Head of Performance, Red Bull-Bora-Hansgrohe; coach to Primož Roglič): Described the specific heat acclimation protocol he uses for Grand Tour preparation — structured Zone 2 sessions in controlled heat, with progressive loading over 10-14 days. He confirmed that the performance benefits extend well beyond hot-weather racing.
Professor Stephen Seiler (polarised training pioneer): Discussed how heat training fits within a polarised model — the sessions should remain predominantly low intensity, with the heat itself providing the additional physiological stimulus. Pushing intensity and heat simultaneously is counterproductive and dangerous.
→ Hear the conversations: Meet All Podcast Guests
Frequently Asked Questions
Does heat training improve FTP? Yes. The research consistently shows FTP improvements of 5-8% from heat acclimation protocols. The mechanism is primarily through increased plasma volume and improved cardiovascular efficiency — your heart pumps more blood per beat, delivering more oxygen to your muscles. These gains are real and measurable, and they apply even when you race in cooler conditions. The 30-watt FTP gains some cyclists report reflect the upper end of what's possible when heat training is combined with structured training.
How do I heat acclimate at home? Close the windows, turn off the fans, add a space heater, and ride your indoor trainer in Zone 2 for 60-90 minutes. Wear an extra layer to raise your microclimate temperature. Start with shorter sessions (45 minutes) and build up over 10-14 days. The key is consistent daily exposure — your body needs the repeated heat stimulus to trigger adaptation. You don't need expensive equipment or a climate chamber. A warm room and discipline are enough.
Is heat training safe for masters riders? It is, with appropriate caution. Heat tolerance does decrease with age — your thermoregulation becomes less responsive and your cardiovascular system has less reserve. Masters riders should start with shorter sessions (30-40 minutes), build more gradually, and use a heart rate ceiling to prevent overreaching. If you have any cardiovascular history, talk to your GP before starting. The adaptations are still available to you — the approach just needs to be more conservative.
How long does heat acclimation last? Full acclimation develops over 10-14 days of consistent heat exposure. The benefits begin to decay after 2-3 weeks without heat sessions, with plasma volume contracting first. By 4-6 weeks, most acute adaptations are lost. To maintain gains, schedule one or two heat sessions per week after your initial block. For event preparation, finish your heat block 3-7 days before race day for peak benefit with adequate recovery.