Altitude Training for Runners: Meta-Analysis of 19 Studies Finds a Small Gain
Altitude training gives middle- and long-distance runners a small performance boost, according to a meta-analysis of 19 studies published on 17 October in the journal Sports Health. One of the authors is Basque physiologist Iñigo Mujika, of the University of the Basque Country. The gain shows up in time trials, but not in VO2max or running economy.
What the altitude training meta-analysis looked at
The authors are Gerasimos Grivas, Nicolas Berryman, Adrien Vachon, Laurent Bosquet and Iñigo Mujika, from universities in Greece, Canada, France and the Basque Country. It is a systematic review and meta-analysis (abstract on PubMed, article in Sports Health).
They searched Medline, Embase, SportDiscus and Web of Science for experimental studies on healthy adult middle- and long-distance runners. They only included studies with a control group that tested real altitude or hypoxic exposure, meaning breathing air with less oxygen, for example in a tent or a hypoxic room. Each study also had to measure at least one of these outcomes:
- time-trial performance;
- maximal oxygen uptake (VO2max);
- aerobic endurance;
- running economy;
- hemoglobin and related values.
Nineteen studies met the criteria. Results were pooled as standardized mean differences, a way of comparing studies that measure things on different scales.
The altitude training results
| Outcome | Effect (SMD) | Significant? |
|---|---|---|
| Time-trial performance | 0.31 | Yes (p below 0.05) |
| VO2max | 0.32 | No (p = 0.07) |
| Aerobic endurance | 0.12 | No (p = 0.47) |
| Running economy | -0.03 | No (p = 0.70) |
| Hemoglobin concentration | 0.77 | Yes (p below 0.001) |
Time-trial performance improved with an effect of 0.31. By convention, 0.2 counts as a small effect and 0.5 as moderate, so the authors call it a small but significant improvement. The confidence interval runs from 0.02 to 0.60, which means the true effect could be close to zero or somewhat larger.
VO2max rose by a similar amount, 0.32, but did not reach statistical significance. Aerobic endurance and running economy did not change in any meaningful way.
Hemoglobin moved the most, with an effect of 0.77. That fits the goal of altitude training: making the body produce more red blood cells to carry more oxygen.
Why hemoglobin rises more than performance
More hemoglobin does not automatically mean a faster race. In the abstract, the authors note that physiological responses were inconsistent across outcomes and protocols. The included studies mix real altitude and simulated hypoxia, each with its own protocol.
So the practical result of altitude training is a small improvement in race times, with no clear change in VO2max or economy, the factors that usually explain distance running performance. Our guide on what VO2 max is explains what each one measures.
What it means for recreational runners
The included studies used trained middle- and long-distance runners, and the average effect was small.
- An altitude training camp may add something, but the abstract does not say which protocol works best or for how long.
- Home hypoxic tents and masks count as hypoxic exposure, but the meta-analysis does not separate their effect from real altitude. Before spending money, keep in mind that the average gain is small.
- Weekly volume, zone 2 training and threshold training remain the basis of progress for a recreational runner, with or without altitude training.
- If you spend a few days training in the mountains, adjust your paces: the higher you go, the harder the same pace feels. Running by feel or by heart rate zones is more reliable than going by your watch.
Limitations of the study
Nineteen studies is a modest base, and each used its own altitude training protocol, which makes it hard to draw a specific prescription. VO2max came close to significance, with p = 0.07, so a small effect cannot be ruled out. The participants were trained middle- and long-distance runners, so it is unclear whether the results apply in the same way to recreational runners.
The journal rates the paper as level 2 evidence. The authors report no conflicts of interest.
Frequently asked questions
Does altitude training make you faster?
According to this meta-analysis, yes, but only a little: altitude or hypoxic exposure was associated with a small but significant improvement in time trials among middle- and long-distance runners.
Does altitude training increase VO2max?
VO2max went up, but the change was not statistically significant (p = 0.07). Hemoglobin concentration did rise clearly.
Are hypoxic tents worth it?
The meta-analysis groups hypoxic exposure with real altitude and finds a small average gain. It cannot tell you whether a home tent is worth its price compared with other ways of training.
Who carried out the study?
A team from Greece, Canada, France and the Basque Country, with Iñigo Mujika of the University of the Basque Country among the authors. It was published in Sports Health on 17 October 2026.
