Prevalence of exercise-induced arterial hypoxemia in healthy women

Exercise-induced arterial hypoxemia (EIAH) is reported to occur in approximately 50% of highly trained male endurance athletes. Few studies have examined EIAH in women and the prevalence remains unclear. It has been reported that some female subjects who develop EIAH possess maximal oxygen consumption (VO2max) values that are within 15% of their predicted value. This is unique to women, where EIAH has generally been reported in men who have a high VO2max. The primary objective of this investigation was to determine the prevalence of EIAH in a large female population with a wide range of VO2max values. It was hypothesized that EIAH would occur with a greater prevalence and at relatively lower predicted VO2max than that previously reported in males.

Young women (N = 52; 26.5 +/- 4.9 yr) performed a cycle test to exhaustion to determine VO2max, and oxyhemoglobin saturation (SaO2) was monitored via pulse oximetry. All subjects were tested during the early follicular phase of their menstrual cycle. A >/= 4% drop in SaO2 represented EIAH.

Values for VO2max were variable (VO2max range: 28.0-61.3 mL x kg(-1) x min(-1)). EIAH was present in 67% of the women with N = 19 displaying mild EIAH (92-94%SaO2) and N = 16 displaying moderate EIAH (87-91%SaO2).

It appears that the prevalence of EIAH in women is slightly greater than the 50% prevalence value that is typically reported for highly fit men.