Exercise physiology.

Abstract

Muscular exercise presents a significant challenge to the lung and gas exchange functions of the respiratory system. The cardiovascular system is thought to be the main limit to maximal exercise performance. The increase in ventilation with exercise is significant, but only in the elderly and highly fit is the pulmonary system a mechanical limit to exercise performance. Although the response in gas exchange is not perfect, the PaO2 remains preserved at the level of rest. As the oxygen delivery fails to meet the metabolic demand of the working muscle, the resultant metabolic acidosis elicits a ventilatory compensation. It is important to remember that the hemostatic and integrative nature of these organ systems can make treating each component as a discreet element very unrealistic and misleading. Muscular exercise remains a superb example of the capacity of the ventilatory/gas exchange systems to adapt to stress.