## BAC vs. Time

Figure 2 shows a computer-generated graph of the Blood Alcohol Concentration (BAC) on the vertical axis vs. Time on the horizontal axis. In this example, a 165 lb. man has consumed three mixed drinks consisting of 1 1/2 oz. of 86 proof liquor and a "mixer" at 8:00 pm, 8:20 pm, and 8:40 pm. It is also assumed that although he has not eaten since mid-day, he has been snacking on pretzels at the bar. As a result, it has been assumed that the time required to absorb each drink is 30 minutes.

Inspection of the graph reveals that from 8:00 pm till 8:50 pm, the rate of alcohol absorption exceeds the rate of elimination and his BAC increases accordingly. From 8:50 pm till 9:40 pm, the BAC plateaus as the rate of absorption decreases and the amount of alcohol in the gastrointestinal tract (GI) decreases. At 9:40 pm, the rate of elimination greatly exceeds the rate of absorption, and the BAC falls according the subject's genetically-determined "burn-off" or elimination rate, which can vary from 0.01 - 0.025 g/100 ml (%) /hr. In this example, the mean elimination rate for men of 0.017 mg/100 ml (%) /hr was used, and all the values were computed according to the well-known Widmark formula.