Introduction: Hypoxia may be induced by either cabin pressure failure or oxygen
system malfunction during flight. Personal tolerance to hypoxia will determine if an
aircrew member will succeed in handling the situation, or their symptoms will lead
to cognitive impairment and eventually unconsciousness. Tolerance to hypoxia can
be examined in altitude chamber training sessions designed to expose aircrew to
hypoxic conditions in a controlled setting. There are several personal factors that
may influence hypoxia tolerance. In this study, we examined whether gender was
one of them.
Methods: During altitude chamber training, the participants were exposed to a
simulated altitude of 25,000 feet (7,620 meters). At this altitude they took off their
oxygen masks, in order to recognize their personal symptoms. During this time,
heart rate and hemoglobin saturation were measured. These measurements were
taken at 10 seconds intervals.
Results: In this retrospective study, the records of 22 women and 145 men were
analyzed. Significant differences in hemoglobin levels were found between men
and women. Women were found to have a significantly higher heart rate during all
stages of the exposure. There were no significant gender-associated differences in
oxygen saturation during hypoxia exposure.
Conclusions: No significant differences were found in oxygen saturation levels
between men and women during hypoxia exposure. Lower hemoglobin levels and
higher heart rates were not associated with changes in oxygen saturation among
women. We conclude that gender does not affect hypoxia tolerance.
Keywords: Blood oxygen saturation, Depressurization system failure, Heart rate, Hypobaric chamber,
Hypoxia, Oxygen system failure.