Effects of two types of hyperventilation on standing balance

International audience; The present study sought to establish links between hyperventilation and postural stability. Eight university students were asked to stand upright under two hyperventilation conditions applied randomly: (1) a metabolic hyperventilation (induced by CO2 rebreathing), and (2) voluntary hyperventilation (set at 25 cycles per minute). Recordings were obtained with eyes open, standing on a force platform over 20-second periods. The ventilatory variations and displacements of the center of pressure in both frontal and sagittal planes were monitored in the time and spectral domains. Postural changes related to respiratory variations were quantified by coherence analysis. Myoelectric activities of the soleus and tibialis anterior muscles were recorded using surface electromyography. Results showed that characteristics of postural perturbation and mechanisms of adjustments markedly differ as the hyperventilation was metabolic or voluntary. These results suggest there is a link between control of respiration and control of posture, although their mechanisms are differently organised.