[Hypoxemia and exhaustion time to maximal aerobic speed in long-distance runners]

A recent paper (Billat et al., 1994a) has shown the reproducibility but also the great variability between subelite long-distance runners in their time to exhaustion at the velocity which elicits VO2max, called the maximal aerobic speed (MAS). The present study delved further into the reasons for this large difference between runners having the same VO2max. The question addressed was whether the exercise-induced hypoxemia (EIH) was more important for athletes having the longest time to exhaustion at 90 (Tlim 90), 100 (Tlim 100), or 105% (Tlim 105) of MAS. The study was conducted on 16 elite male runners. EIH was observed, that is, arterial oxyhemoglobin saturation and arterial partial pressure of oxygen dropped significantly after all the Tlim tests. However, EIH was only correlated with Tlim 90 (r = -0.757; -0.531, respectively).