Physiological Responses to Acute Hypobaric and Normobaric Hypoxia: Differences in Maximal Exercise and Clinical Impact

, including air density, alveolar gas composition, exercise modality, and the age and sex of the individual performing the effort. A thorough understanding of how different hypoxic modalities affect exercise responses provides fundamental insights into human physiology and pathophysiology under extreme conditions, with practical implications for sports medicine and athletic training, as well as for patients with pathologies potentially influenced by hypoxia dealing with high altitude. This narrative review synthesizes current evidence on the differential effects of HH and NH on exercise responses, with an emphasis on maximal exercise capacity and underlying the physiological mechanisms regarding cardiovascular function, ventilatory adaptation, and gas-exchange responses, also outlining the implications for athletes, clinical populations (heart failure, chronic obstructive pulmonary disease, pulmonary hypertension), and altitude medicine.