Exercise Physiology: A Review of Established Concepts and Current Questions

Exercise physiology is the science that studies the processes of physical activity and their impact on the body. It usually requires a multidisciplinary approach with a team of experts because of the multiple physiological systems involved. At the cellular level, exercise can trigger a cascade of events that involve metabolic pathways, muscle recruitment and conditioning, neuromuscular adaptations, and optimization of energy production. On a systematic level, this has involved the cardiovascular system, the respiratory system, the musculoskeletal system, the peripheral and central nervous systems, and even the endocrine system to improve adaptation to meet the demands of exercise, improving strength and endurance with the goal of maximizing performance. This field, which began largely with a focus on the kinetics of oxygen consumption and the relationship between aerobic and anaerobic metabolism, has expanded with technological advancements such as wearable devices, advanced imaging techniques, and genomics, which has allowed for a greater appreciation of the physiologic responses of exercise at the level of molecular and cellular interactions. Recently, this science has evolved into the study of overall health promotion and disease prevention to meet individual fitness needs and goals. This philosophy, which is captured by the motto “Exercise is Medicine”, has been adopted as a Global Health Initiative by the World Health Organization (WHO). Despite the advancements in technology and impactful, large-scale studies, a variety of questions, such as how physical activity interacts with aging to affect physical and cognitive function, how inactivity influences acute and chronic disease states, and how we maximize human performance in extreme conditions like microgravity environments, remain. The purpose of this review is to present and discuss established concepts, controversial topics, and unanswered questions within exercise physiology that have allowed this field to become a science that embraces the overall well-being of individuals.