Training in Your Sleep: High-Altitude Tent Experience Report

Just a week ago, my evening routine consisted of setting the altitude I would sleep at that night in an app. Then the generator would start humming softly. A gentle “tschtsch.” With every breath, the air in my bedroom became a little thinner. For four weeks, I slept in the basecamp of my own home.

Altitude training is nothing new in professional sports. Many athletes rely on it. “Sleep high, train low” is considered the gold standard: sleep at a high altitude, train at a lower one. To really feel the effect, one should spend around 400 hours at altitude. That requires time and money. Four weeks in the Engadin—that’s a serious commitment. And even then, one question remains: does the body actually respond? Are you a so-called “responder” or not? For me, a long stay at altitude simply wasn’t an option. So I looked for an alternative.

That’s how my search for a high-altitude tent began, and I found an option to rent one for four weeks. Before starting, I had a blood test done. The goal was to determine whether my body had enough iron reserves to handle the altitude stimulus and produce more red blood cells. Essentially, to have a before-and-after comparison in black and white.

Setting it up was uneventful. After about an hour, the basecamp was ready. A tent, a hose from the generator through the tilted window, a quiet humming in the background. The first night was primarily technical: at what altitude should we start? How to factor in the starting altitude of my home? How would the body react?

From the second night onward, my girlfriend and I slept at just over 1,300 meters. The plan was clear: increase slowly and give the body time to adjust. The first nights went smoothly, almost uneventfully. Sleep was stable, resting heart rate normal, no real sense of strain. But with each adjustment in altitude, something changed. As we gradually approached 2,000 meters and eventually exceeded it, the difference became noticeable. Not dramatic, but clear enough. Sleep became lighter, and I woke up more often. Despite daily ventilation, the air in the tent remained stuffy. The generator hose ran from the balcony into the bedroom, which meant an open window and high humidity inside the tent.

Every evening, I adjusted the altitude, monitored the oxygen level with an external device, and observed how my body reacted. After four weeks, the tent was taken down. The second blood test showed that I am a moderate responder—about 2 g/L more hemoglobin, a measurable adaptation. Not sensational, but a clear indicator. My girlfriend—also serving here as a control—responded slightly less. This aligns with the research: individual responses to hypoxia vary. For a first altitude block, the result is satisfactory.

Still, I returned the tent. Not because it didn’t work, but because I’m not yet sure if it’s the right long-term approach for me. Studies show that a positive response in the first block is no guarantee of the same effect in a second. There’s also the question of sleep quality, especially in summer, when higher temperatures make nighttime recovery even more challenging.

In the end, it’s a balancing act. The fine line between maximum stimulus and adequate recovery is crucial in professional sports. The higher the level, the thinner the air—literally and figuratively. It’s about those last percentages, and about extracting them without demanding more from the body than it’s ready to give.