The height at which supplemental oxygen is required depends on several factors, including the type of activity, individual health conditions, and regulations. There is no single answer.
Aviation Requirements
For pilots, supplemental oxygen is mandated at different altitudes depending on the regulations and flight duration:
- 14 CFR Part 91 (General Aviation): Supplemental oxygen is required for any portion of a flight exceeding 30 minutes above a certain altitude. While the exact altitude isn't specified uniformly across all references, the information suggests it's around 10,000 - 12,500 feet cabin pressure altitude. (References 1, 3, 7, 8, 10)
- 14 CFR Part 121 (Air Carrier Operations): Above 10,000 feet and up to 12,000 feet, flight crew on flight deck duty require oxygen for flights exceeding 30 minutes. Above 12,000 feet, all flight crew on flight deck duty must use oxygen. (References 1, 4)
Medical Conditions
Certain medical conditions necessitate supplemental oxygen at lower altitudes:
- Sickle Cell Disease: Individuals with sickle cell disease may require oxygen above 7,000 feet (2,100 meters). Those with sickle cell trait may also need it at higher altitudes. (Reference 2)
Mountaineering
In mountaineering, the need for supplemental oxygen depends largely on individual acclimatization, fitness level, and the specific altitude. There's no fixed altitude at which it becomes universally necessary. (Reference 6)
General Altitude Sickness
Altitude sickness is a risk at higher elevations, stemming from reduced oxygen availability due to lower atmospheric pressure. The symptoms and severity vary greatly from person to person. While there's no precise altitude where oxygen becomes definitively necessary, supplemental oxygen becomes increasingly beneficial above 8,000 feet (2,400 meters) for many individuals experiencing altitude sickness symptoms. (Reference 2, 7)
In conclusion, while there are specific regulations regarding oxygen use in aviation at altitudes above 10,000 feet, the need for supplemental oxygen at altitude varies depending on individual factors and activities.
