The effect of maximal interval training for 10 weeks on arterial oxygen saturation during heavy exercise

The purpose of the present study was to investigate the effect of maximal interval training for 10 weeks on arterial oxygen saturation (SaO₂) and ventilatory response during heavy exercise. Seven subjects volunteered for participation in the study. All subjects performed an interval training 4 days per week. Training protocol per day consisted of five periods of exercise of 3-min duration on a cycle ergometer at a power output on 100% maximal oxygen uptake (V̇O₂max), interspersed with 2-min recovery cycle at 50%V̇O₂max. V̇O₂max and ventilatory data measured every week. SaO₂, end-tidal oxygen partial pressure (PETO₂), end-tidal carbon dioxide partial pressure (PETCO₂) and the ventilatory equivalent for oxygen (V̇E/V̇O₂) measured during 5-min heavy exercise at 90%V̇O₂max every other week. V̇O₂max significantly increased from 52.5±4.9 to 60.6±5.8 ml·ml^-1·kg^-1 during the training. Sao₂ reduced significantly from 95.4±1.1 to 93.3±1.8%, similarly PETO₂ and V̇E/V̇O₂ reduced during the training. A significant positive correlation was found among SaO₂, PETO₂ and V̇E/V̇O₂ during heavy exercise (SaO₂-PETO₂, r²=0.48, P<0.05 ; Sao₂-V̇E/V̇O₂, r²= 0.49, P<0.05; PETO₂-V̇E/V̇O₂, r²=0.81, P<0.05). These results suggest that ∼50% of the arterial O₂ desaturation during heavy exercise can be accounted for by low ventilatory response. Therefore the maximal intervsal training induced arterial O₂ desaturation during heavy exercise, which can be half explained by low ventilatory response.