What is the physiological zone defined as?

The physiological zone is defined as the altitude range where individuals are able to function without supplemental oxygen, and the atmospheric conditions are generally manageable for native sea-level dwellers. This zone extends from sea level to 10,000 feet. Within this range, most people can perform tasks adequately without the risk of altitude sickness or significant physiological stress.

Understanding the boundaries of this physiological zone is crucial for pilots and individuals operating in high-altitude environments, as it informs decisions on oxygen use and other physiological considerations when ascending to greater altitudes. Above this limit, the partial pressure of oxygen decreases, starting to challenge the body's ability to maintain adequate oxygenation, leading to the potential for hypoxia and other complications.