ABSTRACT
The purpose of the present study was to investigate the effect of maximal interval training for 10 weeks on arterial oxygen saturation (SaO<SUB>2</SUB>) 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 (VO<SUB>2</SUB>max), interspersed with 2-min recovery cycle at 50%VO<SUB>2</SUB>max. VO<SUB>2</SUB>max and ventilatory data measured every week. SaO<SUB>2</SUB>, end-tidal oxygen partial pressure (PETO<SUB>2</SUB>), end-tidal carbon dioxide partial pressure (PETCO<SUB>2</SUB>) and the ventilatory equivalent for oxygen (VE/VO<SUB>2</SUB>) measured during 5-min heavy exercise at 90%VO<SUB>2</SUB>max every other week. VO<SUB>2</SUB>max significantly increased from 52.5±4.9 to 60.6±5.8 ml⋅ml<SUP>-1</SUP>⋅kg<SUP>-1</SUP> during the training. SaO<SUB>2</SUB> reduced significantly from 95.4±1.1 to 93.3±1.8%, similarly PETO<SUB>2</SUB> and VE/VO<SUB>2</SUB> reduced during the training. A significant positive correlation was found among SaO<SUB>2</SUB>, PETO<SUB>2</SUB> and VE/VO<SUB>2</SUB> during heavy exercise (SaO<SUB>2</SUB>-PETO<SUB>2</SUB>, r<SUP>2</SUP>=0.48, P<0.05 ; SaO<SUB>2</SUB>-VE/VO<SUB>2</SUB>, r<SUP>2</SUP>= 0.49, P<0.05; PETO<SUB>2</SUB> - VE/VO<SUB>2</SUB>, r<SUP>2</SUP>=0.81, P<0.05) . These results suggest that-50% of the arterial O<SUB>2</SUB> desaturation during heavy exercise can be accounted for by low ventilatory response. Therefore the maximal intervsal training induced arterial O<SUB>2</SUB> desaturation during heavy exercise, which can be half explained by low ventilatory response.