Hypoxic exercise enhances post-exercise hypotension compared to normoxic exercise

This study aimed to investigate the effect of aerobic exercise under hypoxic conditions (FiO 2: 14.9%) on post-exercise hypotension compared to normoxic exercise matched for mechanical and physiological intensities. Twenty sedentary men completed three exercise sessions using a crossover design: (1) hypoxic exercise at 50% of peak power output, (2) normoxic exercise at 50% of peak power output (normoxic exercise matched for mechanical intensity), and (3) normoxic exercise with heart rates matched for hypoxic exercise. Expired gases and peripheral and muscle oxygen saturation were measured during the exercise. Blood pressure and hemodynamic variables were assessed before and after each exercise session. Hypoxic exercise and normoxic exercise matched for physiological intensity elicited higher heart rate, oxygen consumption, and ventilation compared to normoxic exercise matched for mechanical intensity (p <0.05). Hypoxic exercise showed the lowest ventilation efficiency (p <0.01) and the most severe systemic and muscle hypoxemia (p <0.01) during exercise. Only hypoxic exercise induced significant post-exercise hypotension (-6.9 mmHg; p <0.01) with a significant increase in common femoral artery diameter during recovery (p <0.05). Our findings suggested that hypoxic exercise significantly enhances post-exercise vasodilation compared to normoxic exercise, resulting in greater post-exercise hypotension. This highlighted hypoxic exercise as a promising strategy for managing hypertension with reduced mechanical stress, particularly beneficial for individuals with low exercise tolerance.