Alcohol intoxication is a temporary state that occurs when ethanol enters the bloodstream and affects the central nervous system. Because the body absorbs alcohol faster than the liver can metabolize it, the blood alcohol concentration (BAC) rises, causing changes in mental and physical function. Alcohol acts as a depressant, slowing down communication pathways in the brain. Intoxication is a progression of distinct stages, with feelings shifting dramatically as the BAC increases.
Initial Changes and the Mild “Buzz”
The initial stage of intoxication, corresponding to a Blood Alcohol Concentration (BAC) between 0.01% and 0.05%, is often experienced as a mild “buzz.” Primary feelings include relaxation and slight euphoria. Individuals may notice a subtle sensation of warmth and a minor reduction in shyness, sometimes referred to as the euphoric stage.
Even though the feeling is largely pleasant and social, the brain shows measurable impairment. Decision-making and reaction time can be subtly compromised at this low BAC. Focusing the eyes and performing complex tasks become marginally more difficult. Lowered inhibition contributes to increased talkativeness and a feeling of greater self-confidence.
Moderate Intoxication and Behavioral Shifts
As alcohol consumption continues, the BAC rises into the moderate range, typically from 0.06% to 0.15%, and the effects become pronounced. This level is commonly associated with being visibly “drunk,” as the depressant effects override the initial euphoria. A noticeable loss of physical coordination develops, making tasks like walking a straight line or maintaining balance difficult. Speech often becomes slurred and louder than normal due to impaired motor control.
Judgment is significantly impaired at this stage, leading to poor decision-making and impulsive behavior. The perception of the environment and the ability to process information are distorted. Emotional volatility is common, manifesting as rapid shifts between happiness, aggression, or melancholy. Reaction time is significantly delayed, compromising the ability to respond to unexpected events.
Severe Impairment and Loss of Function
Intoxication progresses to severe impairment when the BAC reaches 0.16% and higher, marking a transition into medically concerning territory. Physical symptoms dominate the experience, including profound dizziness, vertigo, and an inability to stand or walk without assistance. Nausea and vomiting are likely as the body attempts to purge the excess alcohol.
Mentally, the drinker experiences extreme confusion, disorientation, and stupor. Memory formation is severely compromised, increasing the risk of memory gaps known as blackouts. At BACs above 0.30%, the body’s protective reflexes, such as the gag reflex, become impaired, and consciousness may be lost entirely. This level of suppression can lead to life-threatening complications, including dangerously slowed breathing and heart rate.
Personal Factors That Alter the Experience
The subjective feeling of intoxication and the rate of progression vary significantly among individuals, even with the same amount of alcohol consumed. Body weight and size are significant factors, as alcohol is distributed throughout the body’s water content. Smaller individuals or those with a higher percentage of body fat generally achieve a higher BAC faster. Biological differences, such as having less alcohol dehydrogenase—the enzyme that metabolizes alcohol—mean that alcohol remains in the bloodstream longer for some people, notably women.
A person’s drinking history creates tolerance; frequent drinkers may feel less impaired at higher BAC levels than those who drink rarely. The presence of food in the stomach slows the absorption of alcohol, delaying the peak BAC and reducing the intensity of the feeling. Conversely, drinking quickly or on an empty stomach causes a rapid spike in BAC, intensifying the effects of intoxication.