Ventilatory and heart rate responses at the onset of chair rotation in man.

In the present study, we attempted to confirm whether pulmonary ventilation and heart rate increased immediately after passive chair rotation in man. Inspiratory minute volume (V(I)), tidal volume (V(T)), respiratory frequency (f), and heart rate (HR) were determined by breath-by-breath and beat-by-beat techniques before, during, and after rotation for a total of 45 s. It was found that V(I) significantly increased immediately after chair rotation, but HR remained almost constant. These results suggest that the activation of horizontal semicircular canals is one causal factor of ventilatory response at the onset of exercise with rotational movement in healthy subjects, but heart rate response is not.