Effect of normobaric hypoxia on cardiorespiratory and metabolic risk markers in healthy subjects

The aims of this study were to investigate the influence of hypoxic physical exercise on metabolic risk markers and to compare the effects on maximum oxygen uptake (VO2max), arterial stiffness, and several blood parameters to a control group training under normoxic conditions. Eight healthy men were examined. Each participant performed exercise at a heart rate (HR) corresponding to 60% of the HR at VO2max on a treadmill device for 50 min (including 5 min warm-up and 5 min cool-down) after 30 min rest, on 3 days per week, for 4 weeks, in either normobaric hypoxia or normobaric normoxia. Each participant performed the exercise program under both environmental conditions with a wash-out period of 4 months. Brachial ankle pulse wave velocity after training was significantly lower in the hypoxic group than in the normoxic group (P = 0.02). The VO2max in the hypoxic group was significantly higher after than before training (P = 0.04). Our results suggest that hypoxic training may more effectively reduce arterial stiffness and improve cardiorespiratory function compared with training performed at the same relative exercise intensity under normoxic conditions.