Ventilatory response kinetics and breathing pattern during exercise at different chemoreceptive drives.

For studying the effects of different chemoreceptive drives on the ventilatory responses to muscular work, experiments were carried out with 16 healthy men. They accomplished a 5-min exercise while breathing with different gas mixtures or after hyperventilation. As was shown, the rapid component of the exercise hyperpnea increased with intensifying the hypercapnic and/or hypoxic stimuli and was reduced or abolished with attenuation of these stimuli. At this, hypoxic drive exerted primary influence on the response kinetics. In the steady-state exercise effects of the chemoreceptive stimuli were modulated by biomechanical factors, which leads to a energetically optimum breathing pattern being formed.