BAC are the initials of the English expression Blood Alcohol Concentration – that is, the amount of alcohol in the blood. Measuring BAC is one of the ways police measure how much alcohol you have consumed.
Alcohol is absorbed by the blood through the walls of the stomach and intestines. As more alcohol is consumed, BAC levels increase. However, the exact time it takes for each body to absorb alcohol varies from person to person. This is because many different factors affect BAC, such as:
- the amount of food you have consumed
- the time of day
- your mood
- your metabolism
- fatigue levels
- your sex
Women have fewer bodily fluids than men, so their blood alcohol concentration is proportionally higher. So if a woman who weighs 60 kilos drinks a double gin, then a man of the same size will need to drink a triple gin to get his blood alcohol to the same level.
There is some evidence that women have fewer amounts of the ADH enzyme (which is responsible for the breakdown of alcohol in the liver and stomach walls) and this may play a role in higher BAC levels.