Exercise physiology for graded exercise testing: A primer for the primary care clinician

Exercise testing is an advanced clinical procedure used by providers to assess functional capacity for the purpose of guiding cardiovascular and pulmonary diagnoses and therapies. Numerous clinical guidelines, texts, and consensus statements have been published to assist clinicians in the identification of indications and criteria for treadmill stress testing, as well as procedures for test performance and interpretation [1-4]. However, the physiology of exercise testing, which is the foundation for exercise testing, is often overlooked in resource publications, as well as during the clinical training of providers. Education in exercise physiology is largely limited to the pre-clinical years, despite the fact that progress in cardiovascular exercise physiology is ongoing. This chapter functions as a primer for the primary care clinician who conducts exercise testing: core concepts pertaining to energy metabolism, skeletal muscle physiology, and cardiovascular and pulmonary physiology are reviewed. Additionally current concepts pertaining to testing for maximal aerobic power, factors that influence both test performance and results, and the physiology of myocardial ischemia and ST-segment depression are discussed.