What is the minimum oxygen concentration required to maintain consciousness at sea level?

The minimum oxygen concentration required to maintain consciousness at sea level is approximately 16 percent. At sea level, the atmosphere normally consists of about 21 percent oxygen, which is ample for human survival. When the oxygen concentration drops to around 16 percent, individuals may start to experience symptoms related to hypoxia, which can include impaired cognitive function and decreased physical performance.

This threshold is critical for divers and those engaging in activities at higher altitudes or in environments with variable oxygen content. While it’s essential to understand that environments with lower oxygen levels can lead to unconsciousness and other severe health effects, 16 percent is recognized as the lower limit for sustaining consciousness in a typical sea-level atmosphere. Maintaining oxygen levels above this concentration is crucial for safety and performance during diving and other high-stress physical activities.