During a rapid decompression, the normal time of useful consciousness can decrease by as much as what percentage?

During a rapid decompression, the normal time of useful consciousness can decrease significantly due to the sudden drop in pressure. When a person is exposed to a low-pressure environment, such as during rapid decompression at high altitudes, the body is unable to maintain adequate levels of oxygen in the blood. This can lead to hypoxia, where the brain and other vital organs do not receive sufficient oxygen.

The most widely recognized percentage decrease for the time of useful consciousness in such situations can be as much as 50%. This means that individuals may have as little as half the time to react to the situation, which is critical for making decisions and taking life-preserving actions, such as activating oxygen systems or descending to a safer altitude. The physiological effects of altitude can take a toll on cognitive functioning and awareness, thus the recognition of the urgency for an immediate response is paramount.