How is Blood Alcohol Concentration (BAC) measured?

Blood Alcohol Concentration (BAC) is primarily influenced by an individual's body weight, as it plays a significant role in determining how alcohol is distributed within the body. The greater an individual's body mass, the more blood and bodily fluids are available to dilute the alcohol consumed. This means that two people can consume the same amount of alcohol, but their BAC can differ significantly based on their body weight.

Measuring BAC directly involves using blood tests, breath tests, or urine tests, with the results typically expressed as a percentage of alcohol in the bloodstream. However, body weight is a critical factor in calculating and understanding BAC variations among different individuals.

In assessing the impact of alcohol consumption, the other factors listed—blood pressure, respiratory rate, and heart rate—do not directly measure BAC or influence its calculation. They may be physiological responses to alcohol consumption but do not provide a direct measurement of BAC.