Which stage of hypoxia is characterized by an indifferent state where 10,000 feet may not require supplemental oxygen?

The indifferent stage of hypoxia is characterized by a condition where the body experiences decreased oxygen availability without noticeable signs or symptoms. At altitudes such as 10,000 feet, most individuals still maintain adequate physiological function and may not perceive the need for supplemental oxygen. The body can typically compensate for lower oxygen levels in this stage, allowing for cognitive and physical activities to continue largely unimpaired.

This understanding of the indifferent stage is essential for flight crews and personnel working at altitude, as it provides a clear guideline for when supplemental oxygen becomes critical. Recognizing that this stage is often asymptomatic helps to inform safety procedures and decision-making in aviation and other high-altitude environments.