Respiratory system responses to a maximal apnoea.

A maximal apnoea provides significant challenges to one's physiological systems, including significantly altered arterial blood gases, and requires a highly integrative response from multiple systems, that is, changes in blood pressure, maintenance of cerebral blood flow, etc. Previous work and reviews have focused on the cardiovascular responses to a maximal apnoea, but very little work has focused upon the responses of the respiratory muscles and respiratory mechanics. This is important because of the changes to arterial blood gases leading to an increased drive to breath and the appearance of involuntary respiratory muscle contractions. This review outlines what is known about how the respiratory system responds to a maximal apnoea. We put forth the hypothesis that the respiratory muscles may become fatigued following a maximal apnoea and that the respiratory muscles of elite divers may be more fatigue-resistant, which could be an important feature of these individuals which allows them to be successful in this sport. Finally, we provide direction for future work to explore the long-term health of apnoea diving.