RECRUITMENT OF MUSCULAR ACTIVITY AND THE CENTRAL NEURONE AFTER-DISCHARGE OF HYPERPNEA

Abstract

A study of action potentials of respiratory muscles shows that the use of these muscles is as varied in hyperpnea as in eupnea. In some individuals the extra mechanical energy required for hyperpnea is contributed entirely by the inspiratory muscles, but in most individuals hyperpnea is associated with varying degrees of increased activity of the expiratory muscles as well. The increase in activity of the expiratory muscles is usually of smaller magnitude and of shorter duration than of the inspiratory muscles and in the later stages of hyperpnea expiration which was initially active often becomes purely passive. Active expirations occurring during eupnea are not infrequently abolished at the onset of hyperpnea. The mechanical advantages of such adjustments are discussed.