Final answer:
A person's BAC level can continue to rise even after they become unconscious because the body metabolizes alcohol at a constant rate and alcohol may still be absorbed from the digestive system. Different BAC levels are associated with different levels of intoxication, and individual responses to alcohol vary widely.
Step-by-step explanation:
A person's BAC level will not necessarily stop rising once the person is unconscious. The rate of alcohol metabolism in the body is relatively constant, at approximately 3.3 mmol/L (or 15 mg/dL) per hour, regardless of whether a person is conscious or unconscious. Since alcohol continues to be absorbed into the bloodstream even after a person has stopped drinking and may still be in the digestive system, the BAC can continue to increase.
It's important to understand that the effects of alcohol, such as acute intoxication, unconsciousness, and potential death, are correlated with different BAC levels. The legal limit for intoxication is a BAC of 0.08, but higher levels can lead to more severe consequences. For example, a BAC of about 0.30% may cause unconsciousness, and a BAC of about 0.50% can be fatal.
Given the variation in individual tolerance and responses to alcohol, predicting the exact BAC at which a person will become unconscious is complex, and the BAC can still rise after unconsciousness if more alcohol is absorbed from the stomach and intestines into the bloodstream.