ABSTRACT
The foregoing chapters of this book have described the essential features of the V̇O2 response to exercise both at the level of the muscle and the lung (Chapters 1, 3 and 6); outlined the important theoretical and practical considerations in the measurement and analysis of V̇O2 kinetics (Chapters 2 and 3); highlighted similarities and differences in the response across species (Chapter 5) and in different exercise modalities in humans (Chapter 4); and debated the nature of the physiological mechanisms underpinning both the ‘primary’ and ‘slow’ components of the V̇O2 response to exercise of different intensities (Chapters 7–11). The latter section has included treaties on the possible influence of metabolic factors (Chapters 7 and 9), oxygen availability (Chapter 8) and muscle fibre type (Chapters 10 and 11) on V̇O2 kinetics. The purpose of the present chapter is to summarize much of the preceding discussion in an attempt to move towards a ‘unifying’ concept through which V̇O2 kinetics and their sensitivity to a variety of interventions can be better understood. To facilitate this process, Chapter 12 poses and attempts to answer six key questions:
How closely do pulmonary V̇O2 kinetics represent muscle V̇O2 kinetics?
Does muscle V̇O2 increase immediately at exercise onset?
Does O2 delivery, metabolic inertia or something else, limit the speed of the V̇O2 kinetics?
Are the primary component V̇O2 kinetics slowed above the lactate threshold?
What is the mechanistic basis for the V̇O2 slow component?
How does ‘priming exercise’ influence V̇O2 kinetics?
