The experience commonly described as feeling “drunk” is the physical and cognitive response to a rising or peaked Blood Alcohol Concentration (BAC) in the bloodstream. This feeling encompasses a range of effects, including altered mood, lowered inhibitions, and impaired motor coordination, all proportional to the amount of alcohol reaching the brain. The duration is highly variable, depending on the speed at which the body’s metabolic processes handle the consumed alcohol. The total time from the first drink to complete sobriety is governed by two phases: how quickly the alcohol enters the system and the fixed rate at which the body eliminates it.
Alcohol Absorption and Peak Effects
The onset of the intoxicating feeling begins almost immediately after consumption because alcohol does not require digestion. It moves rapidly from the stomach and small intestine directly into the bloodstream. While some alcohol is absorbed through the stomach lining, the majority of absorption occurs in the small intestine, causing the blood alcohol concentration to climb shortly after the first sip.
The highest point of intoxication, known as the peak BAC, is typically reached between 30 and 90 minutes after the last drink. The speed to this peak depends heavily on stomach contents. Drinking on an empty stomach allows alcohol to pass quickly, leading to a faster and higher peak BAC. Conversely, consuming food slows the rate of gastric emptying, which delays the peak and results in a lower maximum BAC.
The Process and Rate of Alcohol Elimination
Once alcohol has been absorbed, its removal from the body is managed almost entirely by the liver. The liver uses the enzyme alcohol dehydrogenase (ADH) to break down ethanol, the alcohol in beverages, into a less toxic compound called acetaldehyde. This subsequent compound is then further broken down and eventually eliminated from the body. This metabolic pathway dictates the overall duration of the intoxication.
The body metabolizes alcohol at a nearly constant, linear rate, regardless of how much alcohol is in the system. For the average person, the liver can reduce the BAC by approximately 0.015% per hour. This fixed rate means the body cannot speed up the process of sobering up. If an individual reaches a BAC of 0.06%, it will take roughly four hours for the alcohol to be completely eliminated from the bloodstream.
Because the elimination rate is constant, the total time the drunk feeling lasts is determined by the peak BAC achieved. A higher peak BAC means the linear elimination process must continue for a longer period to bring the concentration back to zero. This fixed-rate metabolism is the primary reason why a person may feel the effects of heavy drinking well into the following morning.
Individual Factors Influencing Duration
While the liver’s elimination rate is fixed, various biological and situational factors influence the peak BAC, which determines the total duration of the feeling.
Body Composition
Body weight plays a significant role, as alcohol is diluted by the total amount of water in the body. A heavier individual with higher body water content will have a lower BAC than a lighter individual consuming the same amount of alcohol. Biological sex also accounts for differences due to variations in body composition and enzymes. Women generally have less body water and lower levels of alcohol dehydrogenase in the stomach compared to men of the same weight. This results in less fluid to dilute the alcohol and allows more alcohol to pass directly into the bloodstream.
Genetics and Food
Genetic variations affect the efficiency of the enzymes responsible for breaking down alcohol. Certain populations inherit genes that result in less efficient alcohol dehydrogenase or acetaldehyde dehydrogenase, causing alcohol and its byproducts to remain in the system longer. The presence of food in the stomach slows the absorption rate, spreading the alcohol’s entry over time, which results in a lower peak BAC and a potentially shorter overall time to return to zero BAC.
Distinguishing Sobriety from Residual Impairment
The feeling of euphoria or obvious motor impairment may subside before the body has fully eliminated all the alcohol. While the BAC is declining, a condition known as residual impairment can persist even after the initial “drunk feeling” has passed or the BAC has returned to zero. This impairment includes cognitive deficits like poor reaction time, reduced attention span, and mental fatigue.
Studies show that psychomotor impairment can peak several hours after the BAC has begun to fall, a phenomenon known as the lag effect. The brain remains affected by the recent presence of alcohol, even as the substance is cleared from the blood. Common remedies like drinking coffee, taking a cold shower, or exercising do not affect the liver’s fixed elimination rate. The only mechanism for complete sobriety is allowing sufficient time for the liver to metabolize all the alcohol.