A study I was involved in (1) has shown that Exercise Induced Arterial Hypoxemia (EIAH) occurs in a greater percentage of highly trained persons than previously believed (60% compared to 50%), and also seems to occur in those who are less fit, but to a lesser degree.
While it isn't exactly clear what causes EIAH, a mild to severe decrease in the oxygen content of blood when exercising at or near maximal intensity, discovering the cause of EIAH is important as not understanding this limitation reveals our incomplete understanding the physiology cardiorespiratory function.
Our study won't have any immediate impact on thinking about how we should exercise but it does add to the growing knowledge base needed to understand EIAH.
Study subjects were pushed to their limits either on a stationary bike, treadmill, or both. We looked at blood lactate levels, lung volume and air flow pre-post exercise, and arterial blood oxygen levels. We were able to demonstrate that air flow restriction did not influence EIAH.
Our study was the largest of it's kind to date with 82 subjects. Go to the link below to read about what we did.