Abstract
Control of ventilation was studied by measuring resting and hypercapnic ventilatory drives using a rebreathing technique in a group of 35 young male swimmers who were compared with two groups of 13 men and 10 women.
1) Mouth pressure during airway occlusion 0.1sec. after the onset of inspiration, P0.1 at rest in room air breathing were not significantly different in the three groups.
2) Ventilatory responses to CO2 by VE/PACO2 were 1.89±0.83L/min./mmHg in the group of healthy men, 1.17±0.32 in the group of healthy women and 1.88±0.78 in a group of swimmers. These results were lower than values reported by Read et al. and Altose et al. Hypercapnic ventilatory drive as measured by the slope of VE/PACO2 in a group of healthy women was apparently lower than that of the other groups.
3) Mouth occlusion pressure in response to CO2, P0.1/PACO2 was 0.39±0.20cm H2O/mmHg in healthy men, 0.25±0.15 in healthy women and 0.39±0.17 in swimmers. These results indicate that chemosensitivity as determined by P0.1/PACO2 was lower in healthy women than in others, but the difference was not significant.
4) Subjects with decrease in hypercapnic ventilatory drive as shown by ventilatory response by VE/PACO2 and P0.1/PACO2 i.e. so-called “low responders” were observed more in the group of swimmers than in healthy men.
