s: blood-alcohol-concentration D: Information on blood alcohol concentration & what it means. Learn about different blood-alcohol levels.

Pretty much everyone knows that a person’s level of intoxication can be measured by their blood alcohol concentration (BAC). Yet very few people understand what these different levels mean or how quickly one reaches them. This information will tell you everything you need to know about blood-alcohol concentration and answer some of the more common questions about BAC and drinking.

An explanation of different blood alcohol levels

Though there are a number of different factors that can impact a person’s blood alcohol level, as discussed below, the following chart provides information on the effects of different blood alcohol levels and the average number of drinks it takes to get there.

Average # of drinks Effects 1 No overt effects, only a slight mood elevation 2 Warmth, relaxation, a slight decrease in reaction time and muscle coordination 3 Slightly impaired speech, balance, vision, and hearing; euphoric feelings, increased confidence, loss of motor coordination Legally intoxicated in all states Coordination and balance become difficult, impaired mental faculties and impaired judgment Major physical and mental impairment, slurred speech, blurred vision, poor motor skills Mental confusion, trouble moving about without assistance Severe intoxication, little conscious control of mind/body Likely unconscious/threshold of coma Deep coma Death from respiratory arrest

Legal blood alcohol limit for driving

The legal limit for driving is 0.08 in most states, and 0.10 pretty much everywhere else.

Deadly blood alcohol levels: How much alcohol does it take to kill a person?

The lethal limit for alcohol is typically between 0.4% and 0.6% volume by blood, depending on the person. (Pociluyko, 2003) While the deadly dose will vary by person, “it takes approximately the same concentration of alcohol in the body to kill a nondrinker as to kill someone who drinks on a regular basis.” (Hanson et al., 2004, p. 188)

Factors that influence blood-alcohol concentration

In healthy individuals, 95% of alcohol will be metabolized by the liver. Yet if the liver can’t keep up, excessive amounts will spill into the bloodstream, raising blood alcohol concentration. The faster alcohol is consumed the higher the BAC, which is why many alcohol overdose deaths on college campuses occur when young men and women are funneling alcohol down their throat or otherwise consuming large quantities very quickly.

Many other factors play a role as well. “The blood alcohol level produced depends on the presence of food in the stomach, the rate of alcohol consumption, the concentration of the alcohol, and the drinker’s body composition,” write Hanson, Venturelli & Fleckenstein. “Fatty foods, meat, and milk slow the absorption of alcohol, allowing more time for its metabolism and reducing the peak concentration in the blood. When alcoholic beverages are taken with a substantial meal, peak BACs may be as much as 50% lower than they would have been had the alcohol been consumed by itself.” (2004, p. 185) Things like fear, stress, nausea, and exercise can also influence stomach contents and alter alcohol absorption.

Mixing liquor with diet soda leads to a higher blood-alcohol concentration than mixing it with regular soda, because of the way that artificial sucrose fools the body and affects its metabolism. (Marczinski & Stamatas, 2012) Because muscle has more fluid volume than fat, BAC also depends on muscle mass. If two men weigh the same amount, the leaner, more muscular man will show fewer effects from the same amount of alcohol. This is one of the reasons women are more affected by alcohol than men: they have more body fat and less muscle mass.