LOW AMPLITUDE DAILY CHANGES IN REFLEX VENTILATORY RESPONSE TO PROGRESSIVE ISOCAPNIC HYPOXIA

Daily changes in reflex ventilatory responses to hypoxia were studied in 56 young healthy men participated. A rebreathing technique - progressive isocapnic hypoxia -was used to measure hypoxic chemoreflex reactivity. The measurements were repeated every 3 hours during a 24-hour period. The ventilatory response to hypoxia - analyzed as the relationships (slope) MV/SaΟ 2 (minute ventilation/arterial oxygen blood saturation) and P 0.1 /SaΟ 2 (mouth occlusion pressure/oxygen arterial blood saturation) remained relatively stable throughout the examined period exhibiting lowamplitude differences from one another with the maximum variation at 12:00 hours.