Pulmonary Responses to Exercise
Along with cardiovascular physiology and responses to exercise, the function of the lungs, in concert with cardiovascular function, is also a huge academic and research interest of mine. The field of exercise physiology undervalues the role of the lung in exercise tolerance, and especially in the contribution of the work of ventilation to increases in whole body VO2 during more intense (high ventilation rate) exercise. Such an oxygen cost can be as much as 15% of the whole body VO2 response, has the potential to change the kinetics of whole body VO2 with increasing exercise, yet seldom do textbooks and research manuscripts acknowledge this contribution; preferring to stick with the holistic black box approach where contracting muscle accounts for all exercise VO2 responses. From an academic perspective, the study of lung function in gas exchange is important and has application to exercise, clinical aspects of cardio-pulmonary function, and also for understanding the changes in human physiology during acute and chronic exposure to hypobaric hypoxia (increased altitude). Surfactant is important in optimizing lung ventilation to perfusion matching and therefore gas exchange, lowering the work of ventilation, and provides interesting insight to applications of mechanics to lung function. And of course, as illustrated in the left figure, red blood cells are vital for the transport of O2 and CO2 throughout the vascular space. As such, the red blood cell connects the external respiration of the lung to the internal respiration of the tissues. Each site of gas exchange has its own unique regulatory framework, and one of the perplexing features of pulmonary physiology is that we still do not have the equipment to study the intricate features of gas exchange in-vivo. Perhaps this is part of the mystery of this field that attracts much of my interest. I hope you are an intrigued as I am with the Topics within this Section.
Recommended sequence of topics:
Mechanics of ventilation
Spirometry measurement of lung volumes and capacities
Gas partial pressures
Alveolar gas diffusion
Blood oxygen transport
Blood carbon dioxide transport
Ventilation during exercise
Understanding the ventilation threshold
How is ventilation controlled?