Thin air, thicker blood? hypoxia training may supercharge red blood cell production — at a cost

This trial tests whether exercising in low-oxygen conditions (intermittent hypoxia) can stimulate the body to produce more red blood cells compared to normal-oxygen training. Thirty-two male mountain athletes follow a three-week program, with half training under hypoxia and half under normal air, while all receive daily iron and vitamin supplements. The goal is to see if hypoxia training boosts hemoglobin and red blood cell counts — and whether it dangerously depletes the body's iron reserves.