The authors hypothesised that specific muscular adaptations improve endurance performance following intermittent hypoxic training.
For six weeks (within their normal training), the subjects – 15 male elite level long distance runners – integrated a modified live-low/ train-high (LLTH) programme consisting of two weekly controlled training sessions performed at their second ventilatory threshold.
The athletes were assigned to either a normoxic (sea level) or hypoxic group (O2 levels at 14.5%). Oxygen uptake, and speed at second ventilatory threshold, maximal oxygen uptake (VO2 max) and time to exhaustion (at a constant load at VO2 max) were determined before and after training.
VO2 max and time to exhaustion increased specifically in the hypoxic group, and at molecular level, the athletes’ response to hypoxia was to increase hypoxia-inducible factor 1 alpha, an expression that resulted in the athletes’s cells becoming more adaptable to low-oxygen conditions.
This suggests that this protocol of hypoxic training will help increase oxygen carrying capacity, management of performance at hypoxia and time to exhaustion in endurance runners.