Pulmonary circulation has long been known to have specific proprieties of recruitment and distention to keep the hemodynamic pressure low even when facing very high blood flow. Aerobic exercise especially at high intensity has the particularity to increase considerably the cardiac output. The ability of the pulmonary circulation to face high blood flow with maintaining low pressures is considered as the pulmonary vascular reserve. Furthermore, high pulmonary vascular reserve has been shown to be characterized by low pulmonary vascular resistance, high pulmonary vascular distensibility, high pulmonary capillary volume, and high lung diffusing capacity allowing for lower ventilation at a same metabolic cost. The pulmonary vascular reserve thus reflects the capacity of the pulmonary circulation, including the capillary network, to adapt to high exercise levels. Interestingly, a high pulmonary vascular reserve is an advantage as it is associated with a superior aerobic exercise capacity (VO2max). This observation strongly suggests that exercise capacity is modulated by the functional state of the pulmonary circulation. However, why or when pulmonary vascular reserve may be related to a higher aerobic exercise capacity remains incompletely understood. The present chapter will discuss the role of each component of the pulmonary vascular reserve during exercise and develop the factors able to influence the pulmonary vascular reserve in heathy individuals.
Part of the book: Interventional Pulmonology and Pulmonary Hypertension