It’s finally Friday, and you can’t wait for five o’clock to roll around. You work so hard during the week, nobody can blame you for wanting a night out on the town—and since you haven’t seen your friends in ages, it’s a perfect opportunity to get out and celebrate.
Unfortunately, many weekends quickly turn sour when a friend has too much to drink and gets behind the wheel. In this article, you can be better prepared to enjoy your celebrations by understanding how alcohol affects your body—and when you may have had too much to drive safely.
What Is Blood Alcohol Content?
When you drink alcoholic beverages, the alcohol from each drink is absorbed into your bloodstream, acting as a relaxant to both your body and brain. The amount of alcohol in a person’s system, called their blood alcohol content, can be measured within 30 minutes to an hour after a person has had a drink.
Blood alcohol content (BAC) is technically the weight of alcohol per unit of volume of blood. Put simply, it is literally the amount of alcohol present in a person’s bloodstream expressed as a percentage. For example, a reading of .02 BAC means that two-tenths of a percent of the person’s blood is alcohol.
What Factors Affect a Person’s BAC?
Different people can have widely varying BAC levels even if they consume the same kinds of drinks—or even have the same number of drinks. How quickly an individual’s BAC rises depends on a number of factors, including:
- Time spent drinking. Your body needs time to properly process and dispose of the alcohol in your system. Consuming two or three drinks quickly (such as shots of hard liquor) will result in a higher BAC than if you consumed three drinks over the course of a few hours.
- The number of drinks. The only certainty about BAC levels are that they continue to rise with each drink consumed. The standard “one drink” is generally considered to be half an ounce of alcohol—roughly the amount in one shot of liquor, a 5-ounce glass of wine, or 12 ounces of beer.
- Whether you are male or female. Women generally get drunk more quickly and take longer to process alcohol than men of a similar size.
- How much you weigh. Alcohol tolerance tends to rise along with body weight, since a higher body mass means more water (diluting the alcohol of each drink).
- When you last ate. Drinking on an empty stomach causes BAC to rise sharply, as there is no food in your system to absorb the alcohol.
- When you stop drinking. Many people fail to realize that BAC continues to climb for nearly an hour after they have consumed their last drink.
How Can I Tell If I am Too Drunk to Drive?
In the United States, it is illegal to drive with a BAC of .08 percent or higher. However, a person’s response times and attention span can be affected by alcohol even at much lower levels. Just because you haven’t reached the legal limit does not mean you are “ok to drive.”
Symptoms of drunkenness at each BAC level will vary from person to person. Some people may act and respond normally even though they are heavily intoxicated, others may have slurred speech, be unable to answer simple questions, or remember easily-recalled information. Many people have difficulty noticing when their friends are drunk, and cannot accurately assess their own levels of intoxication.
It is important to remember that BAC is only one way to determine if someone is impaired. A person with a “legal” amount of alcohol in his bloodstream may still be tired after a long night out, or be taking medication that decreases response times. For this reason, it is a good idea for anyone who is showing signs of impairment to take a cab home rather than risk causing an accident.
A good rule of thumb: if you think you are too drunk to drive, then you probably are. You have to make plans with your friends to make sure everyone can come out, so why not add a plan for getting home at the end of the night? Before you leave home, designate a sober driver, install a ride-sharing app on your phone, or plan to stay at a friend’s house within walking distance of the bar. You can also help protect your friends by finding a safe way for them to get home after a night of drinking, and by sharing this article on Facebook to remind them that a good night ends only when every person gets home safely!