Randomized trial investigates SpO2 breakpoints during hypoxic exercise in adults, suggesting moderate exercise has limited cardiopulmonary challenge.
Key Points
This study aimed to identify the SpO2 breakpoint during steady-state hypoxic exercise and assess the influence of sex, age, and fitness level on this breakpoint.
Twenty-six physically active adults participated in a two-day study.
Participants performed a treadmill VO2 max test and then completed a hypoxic walking exercise at ~50% of their VO2 max.
SpO2 was continuously measured and analyzed to find individual breakpoints.
Mean breakpoint occurred at an SpO2 of 90.7±2.8% at the 0.17 FiO2 stage.
No significant differences in breakpoint SpO2 or timing were found based on sex (p = 0.961), age (p = 0.953), or fitness level (p = 0.992).
These results imply moderate hypoxic exercise does not challenge oxygen transport enough to show individual variations.