Effects of training on the ventilatory response to hypoxia.

ABSTRACT

The purpose of the present study was to examine the influence of systematical training on the ventilatory response to hypoxia. A rebreathing technique - progressive isocapnic hypoxia - was used to measure hypoxic chemoreflex reactivity. The ventilatory response was measured in a group of 22 world class adult kayakers (22.6 +/-1.9 yr), 16 young kayakers (17.8 +/-1.1 yr), and 38 control subjects (21.9 +/-1.9 yr). The ventilatory response to hypoxia - analyzed as the relationship (slope) MV/SaO(2) (minute ventilation/oxygen arterial blood saturation) - in the adult kayakers was significantly lower (-1.03 +/-0.28 L/min/%, P<0.01) compared with those in the control group (-1.81 +/-0.54 L/min/%) and the young kayakers (-1.54 +/-0.6 L/min/%; the difference between the latter two was insignificant). The following values of P(0.1)/SaO(2) (mouth occlusion pressure/oxygen arterial blood saturation) relationship were found for the investigated groups adult kayakers (-0.20 +/-0.1 cm H/(2)O/%, P<0.05), young kayakers (-0.47 +/-0.1 cm H/(2)O/%, N.S.), control group (-0.48 +/-0.18 cm H(2)O/%). Correlation between the hypoxic ventilatory response and VO(2)max was significant in both groups of kayakers. These findings indicate that tolerance for hypoxia was elevated in the group of athletes compared with the control group. Hypoxic tolerance correlates with the duration of training.