Exercise induced hypoxemia at moderate altitude: comparison between running and roller skiing field test in young elite biathletes

Aim. Exercise induced hypoxemia (EIH) can develop in highly trained endurance athletes in terms of exercise mode, muscle mass involved in the exercise, training status and altitude. With this background, the present study compared EIH development and cardiorespiratory responses, in younger highly trained biathletes, at moderate altitude, during running and roller ski field tests. Methods. Ten younger (15.3 +/- 1.5 years) highly trained biathletes performed two incremental maximal field tests (Leger Boucher test) in running (R) and in roller skiing (RS), at 1850 meters altitude. EIH (haemoglobin O-2 saturation (SpO(2)) decreased >= 4% from baseline) was measured indirectly using an ear-lobe pulse oximeter included in the K4 (Cosmed) used for measured cardiorespiratory responses. Results. During the R test, 9 athletes developed EIH whereas only 7 in SR test. Tests duration was the same furthermore at the end of tests, fall of SpO(2) was significantly higher in R compared to RS (-9.11 +/- 1.51 vs. -5.89 +/- 1.09; P<0.01). SpO(2) was significantly lower in R compared to RS from 75% of VO2max to VO2max (P<0.05). VO2max was significantly higher in R than in RS (61.33 +/- 6.36 vs. 57 +/- 6.60 mL.min(-1).kg(-1); P<0.001). No difference of maximal heart rate, global ventilation, tidal volume or respiratory frequency was present during and at the end of tests. Conclusion. We concluded that prevalence and severity of EIH was more important during R than RS exercises and that EIH differences may be due to a greater gas exchange abnormality in R.