Heat Training as an Alternative to Altitude Training
Summary: This article explores a potential alternative to classic altitude training: creating heat stress through low-intensity training in a very hot room. The main question is whether heat training can provide similar adaptations to altitude, particularly related to oxygen transport. A Norwegian study, summarized in a news article so far, reports that elite cyclists who trained calmly in heat several times a week experienced changes comparable to the effects of high-altitude exposure. The conclusion is that the results sound promising, but published, controlled data is needed before drawing firm conclusions or making practical recommendations.
Introduction
Elite athletes are always chasing those small margins that can decide big races. Everything from volume and intensity to strength training—new ideas constantly emerge on what is most effective. Here we take a look at a possible alternative to classic altitude training: training in heat.
Why altitude training works
Altitude training has been used for decades. By living, sleeping, and training at altitudes above about 1,600 meters above sea level (m.a.s.l.), where the oxygen pressure is lower, the body responds by producing more red blood cells and altering blood plasma—which can eventually lead to an improved ability to transport and take up oxygen. This is an adaptation to the lower oxygen availability. When the athlete then returns to lower altitude, there is often an increased amount of red blood cells—a kind of "natural doping" (Ericsson, 2016).
Drawbacks and practical obstacles
It sounds great, but altitude training requires good knowledge and careful monitoring. Responses vary between individuals—some are sometimes called "responders," others not. High-altitude exposure also entails an increased risk of becoming ill, and there are other downsides such as lost appetite, poorer sleep, and increased risk of overtraining due to impaired aerobic capacity (Ericsson, 2016).
Altitude training remains an important part of preparations for major championships for many. Petter Northug and several cyclists have built successes on this—but issues like overload and overtraining during camps are not uncommon. It's also difficult to study altitude training scientifically: to get the effect, the stay should be at least around 10 days at relatively high altitude, which demands considerations for economy, work, and family logistics.
But what if there's a method that offers similar effects without travel and large costs? That's exactly what a new Norwegian study is trying to investigate: can training in heat improve endurance-related factors?
The Norwegian Study on Training and Heat
The study has yet to be published in full; our source is an article from Norsk rikskringkasting (NRK) that summarizes the project. The investigation was conducted by Høgskolen i Innlandet with Professor of Exercise Physiology Bent Rønnestad at the helm. Rønnestad is known for several solid studies on endurance athletes.
Hypothesis: calm, short training in a warm room, five times a week, increases the body's ability to transport oxygen to the muscles—thus raising hemoglobin levels, just like altitude training.
Setup
In brief: a group of young, promising elite cyclists trained at low intensity on a trainer for 50–60 minutes per session, five times a week, for five weeks. The training room was a shower room where the ventilation had been taped shut. The temperature was kept around 40 degrees, and the humidity about 70 percent—essentially an environment most can technically recreate at home or in a communal training facility.
Reported Results and Uncertainty
The reported result: this heat training over five weeks resulted, according to the article, in the same hemoglobin adaptation as 3–4 weeks of continuous stay at about 3,000 meters elevation. However, it is not clear in the NRK article if the study had a control group or how the conclusions relate to previous altitude training research.
One of the participants, Petter Fagerhaug (a young, promising mountain biker and overall winner of the U23 World Cup in 2018), says that after the experiment, he went to Spain for a training camp and felt better than ever.
Bent Rønnestad describes the results as striking and hopes to expand research in the area. If the results hold, heat training can have significant implications for many athletes.
Quote: “It gives some training possibilities. If you want, you can find a warm room at home, sit there and cycle calmly for 50–60 minutes and achieve the same effect as altitude training. You don't have to be away from family and friends, and you can still do hard sessions outside as usual.”
– Professor of Exercise Physiology, Bent Rønnestad.
Conclusion
We look forward to when more detailed research is released! It's exciting to think about how heat training can open new opportunities for both elite athletes and enthusiasts. Questions that are interesting to follow further: how does heat training stand in a broader perspective with polarized training over time? Can the results be increased further? Heat training at 3,000 meters altitude perhaps? 😉
In summary (our reasoning remains): there are promising indications that repeated low-intensity training in heat can provide similar hematological adaptations as some forms of altitude training, but details and robust controlled data are still lacking. Keep an eye out for published research!
Sources:
https://www.nrk.no/ho/oppsiktsvekkende-resultater-av-trening-i-hoy-varme-1.14503420
- Ericsson. (2016). Cycling Training – Training Theory for Road and MTB. Stockholm. Sisu Idrottsböcker.