Umm...pretty sure that's bullshit.
The extra red blood cells and oxygen-carrying capacity gained from high-altitude training typically last about
2 to 3 weeks (14 to 21 days) after returning to sea level. The benefits start to fade as old red blood cells die off and the body slows down its extra production in lower altitudes. [
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How the Process Works
- Lower oxygen: High altitude has less oxygen in the air.
- Kidney signal: Kidneys sense this and release a hormone called EPO.
- New blood: EPO tells bone marrow to make more red blood cells.
- Return loss: Sea level air has more oxygen, so EPO levels drop quickly. [1, 2, 3, 4, 5]
Timeline of Altitude Benefits
| Phase | Timeframe | What Happens |
|---|
| During training | Weeks 1–4 | Red blood cells increase; blood thickens slightly. |
| Peak benefit | Days 1–10 at sea level | Best oxygen delivery; high performance capacity. |
| Fading phase | Weeks 2–3 at sea level | Excess red blood cells break down; levels normalize. |
| Baseline return | After 4 weeks | Blood counts return to normal pre-altitude levels. |