Does Weight Affect Alcohol Tolerance?

Does Weight Affect Alcohol Tolerance
Absorption Rate Factors // Rev. James E. McDonald, C.S.C., Center for Student Well-Being // University of Notre Dame Many factors influence your body’s ability to absorb and tolerate alcohol. For example, consider the factor of biological sex: Women have less dehydrogenase, the enzyme that breaks down alcohol in the stomach, which contributes to higher BACs than men drinking the same amount of alcohol.

Hormone levels also affect the body’s ability to process alcohol, and women will experience higher BACs drinking their regular amount of alcohol right before menstruation. Women tend to have a higher percentage of body fat and a lower percentage of water. Additionally, the less you weigh, the more you will be affected by a given amount of alcohol.

For people of the same weight, even the same gender, individuals with a lower percentage of body fat will have lower BAC’s than those with a higher percentage of body fat.

Bud = 185 lbs. Ethel = 130 lbs.
2 drinks/ 1 hr.=,025 2 drinks/ 1 hr.053
3 drinks/ 1 hr.=,045 3 drinks/ 1 hr.088
5 drinks/ 1 hr.=.085 4 drinks/ 2 hrs.=,106

Does body fat affect alcohol tolerance?

Alcohol Absorption Rate FAQs – How long does it take for the body to absorb alcohol? Alcohol burns off at a rate of,016 BAC per hour, which is equal to about one standard drink each hour depending on the person’s weight. This rate is true regardless of the size of the person’s body.

  • A 5’3″ female will burn off alcohol at the same rate as an overweight 6’1″ male.
  • How does body fat affect alcohol absorption? Alcohol absorption varies depending upon the person’s body fat level.
  • For instance, a person with a higher percentage of body fat will be slower to absorb alcohol than someone with less.

When two people of the same weight but different body fat levels drink the same amount, the person with less fat will absorb the alcohol faster than the one with more body fat. However, the absorption of the alcohol will metabolize at the same rate. How long does it take to burn off alcohol? With a BAC of 0.08% (legal limit), it will take approximately 5 hours to reach 0.

  1. For a BAC of 0.10%, it will take approximately 6.25 hours to reach 0, and for a BAC of 0.16% (2x the legal limit), it will take approximately 10 hours to reach 0.
  2. For someone with a BAC of 0.20%, it will take around 12.5 hours to reach 0.
  3. I have a high tolerance.
  4. How does that affect BAC? This is called functional tolerance which is the body’s decrease in sensitivity to the effects of alcohol.

While a person exhibiting functional tolerance will not seem as intoxicated as someone with little or no functional tolerance, it’s important to know that this behavioral adaption has no effect on the liver’s ability to eliminate alcohol at the rate of one drink per hour.

Does fat or muscle affect alcohol tolerance?

Factors that impact BAC – Number of standard drinks and rate of consumption

BAC will rise relative to the number of drinks consumed and how quickly they are consumed.

Body size and composition

Body size determines the amount of space that alcohol has to diffuse throughout the body. In general, a person with a larger build who drinks the same as a person with a smaller build will have a lower BAC due to the amount of space alcohol has to distribute through. Alcohol diffuses more into muscle than fat because muscle tissue has a large amount of blood that flows through it. This means that an individual’s muscle to body fat ratio will impact their BAC, as it correlates to the amount of blood available for alcohol to enter. For example, someone with a higher percentage of body fat will experience a more rapid increase in BAC, as alcohol will become more concentrated in the blood of their muscle tissue.

Testosterone and estrogen levels

People with higher levels of testosterone generally have more muscle mass and less body fat than people with higher levels of estrogen. Muscle contains more blood than body fat. The larger volume of blood in those with greater muscle mass allows alcohol to dilute more through the bloodstream and BAC to remain lower. People with higher levels of testosterone are composed of approximately 55-65% water, whereas people with higher levels of estrogen are composed of about 45-55% water. Alcohol becomes more diluted in bodies with greater volumes of water, resulting in lower BAC levels for people with higher levels of testosterone as compared to those with higher levels of estrogen. Individuals with higher levels of testosterone have higher levels of alcohol dehydrogenase, an enzyme that helps break down alcohol. This means that individuals with higher levels of testosterone can more efficiently break down alcohol as compared to individuals with higher levels of estrogen, who have more alcohol enter their bloodstream, resulting in higher BAC levels. Research has found that due to changes in hormone levels, individuals who have periods experience slower alcohol metabolism and higher levels of intoxication in the week leading up to their period. Oral contraceptives and other medications with estrogen also slow the rate at which individuals process alcohol.

Additional drugs or medications

Other drugs and medications, even those prescribed to you, can have adverse effects and unpredictable interactions with alcohol. It is important to ask your doctor if any medications you might be taking have harmful effects when taken with alcohol.

Amount of food consumed

Food present in the stomach causes the alcohol to move down into the small intestine slower than it would on an empty stomach. While it’s a common myth that food absorbs alcohol like a sponge, it actually causes a “traffic jam” in the body, making the processing of alcohol take longer. This reduces the risk of a rapidly rising BAC level.

Emotional state, mood and level of fatigue

Alcohol has a more pronounced effect on those who may be fatigued or under stress. Since alcohol is a depressant, someone who is depressed may experience heightened signs of depression upon drinking.

Menstrual cycle

Research has found that due to changes in hormone levels, individuals who have periods experience slower alcohol metabolism and higher levels of intoxication in the week leading up to their period.

Type of beverage or mixer

Fruit juices slow down the processing of alcohol because the sugar requires digestion, resulting in a slower rise in BAC. On the other hand, carbonated mixers or drinks can cause BAC to rise more rapidly because the carbonation speeds up absorption.

It is important to note that common strategies used to “sober up,” such as taking a cold shower, sleeping, drinking water and consuming caffeine, do not work to lower BAC. The only thing that can help alcohol leave your bloodstream is time.

Can a person’s size or weight affect their response to alcohol?

Your weight – The extent of alcohol’s effect on the central nervous system depends on how much is in your blood and how much blood you have. This is because alcohol is distributed through the body by the water in your bloodstream, according to the NIAAA.

  • The more water in your blood, the more diluted the alcohol will be.
  • Generally, the lower your body weight, the less blood and water you have.
  • So, smaller people usually have a higher ratio of alcohol in their blood if they drink the same amount a heavier person drinks.
  • For most people, intoxication begins to occur after two to three drinks, but it can occur more quickly, with fewer drinks in a lighter person.

Keep in mind that the alcohol content of different types of beer, wine, and distilled spirits can vary a lot.

Does body weight matter in alcohol?

Impact of Body Weight and Body Type on BAC Levels A person’s body weight and body type are factors which have an impact on blood alcohol concentration. In general, the less you weigh the more you will be affected by a given amount of alcohol because the alcohol has less room to spread out, making the concentration higher.

As detailed above, alcohol has an affinity for water, so the more water there is in which to distribute the alcohol, the lower the blood alcohol concentration will be. Basically a person’s blood alcohol concentration is a function of the total amount of alcohol in the person’s system divided by total body water.

Therefore, if two individuals with different weights but similar body fat compositions consume the same amount of alcohol, the larger individual will achieve lower alcohol concentrations than the smaller one because there is more room for the alcohol to spread out.

  • To illustrate this point consider the following: imagine a drop of blue dye is put into both a shot glass and a gallon jug which are both full of water.
  • The concentration of blue dye per unit of measurement in the smaller container (the shot glass) will be greater (the water will be more blue) than in the larger container (the gallon jug) because there is less space for the dye to spread out.

Larger people are simply larger containers than smaller people, so assuming the same quantity of alcohol is ingested, smaller people will be expected to reach a higher blood alcohol concentration than larger people. Similarly, if two people of the same weight consume the same amount of alcohol, a person with a higher percentage of fat will be reach a higher peak blood alcohol concentration than a lean, muscular individual because fatty tissue does not contain very much water and will not absorb very much alcohol, making the concentration in the rest of the body higher for the person with the higher percentage of fat.

How to increase alcohol tolerance?

As pubs and bars reopen across England, many are excited about the opportunity to enjoy a drink with friends and family. While some evidence suggests alcohol consumption increased during lockdown, other reports suggest that over one in three adults drank less – or stopped altogether.

  • But though we may be excited to get back to the pub, our tolerance may be lower than it was pre-lockdown.
  • Regularly drinking a certain amount of alcohol (for example, having four pints every Friday evening after work) can lead to increased tolerance,
  • This is where the brain adapts to the effects of alcohol (such as relaxation and improved mood), and over time more alcohol is needed to achieve the same effects.
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In this scenario you may need to drink five pints to get the same initial “buzz” you got from four pints. Tolerance is a hallmark feature of addiction, But it can also develop with regular and continued alcohol use in social drinkers. Following a period of reduced alcohol use or abstinence, alcohol tolerance can decrease to levels before regular use.

Can you handle more alcohol if you are bigger?

7 Reasons You’re Drunker Than Your Friends Aug.4, 2011— – intro: Think you know your level of alcohol tolerance? Think you know how many drinks it’ll take you to get tipsy? Think again. Most alcohol recommendations are based on a 155-lb. adult male. Usually, drinking three standard-sized beverages – like a 12 oz.

Beer – consumed in under an hour can get the average man drunk. But some experts say that many people don’t know their level of tolerance. In fact, there are genetic, biological and physical factors that can make you drunk faster. Here’s a look at a few characteristics that contribute to your alcohol tolerance: quicklist: 1category: Handling Your Alcohol Consumptiontitle: Size url: text: No, not height.

Weight. The larger you are, the more alcohol you are able to consume before you begin to feel tipsy. “We, in general, metabolize one drink an hour,” said Dr. Corey Slovis, chairman of the department of emergency medicine at Vanderbilt University Medical Center.

  • Ethnic background is an uncontrollable characteristic that factors into whether a person can drink more and hurt less.
  • “The enzyme that metabolizes alcohol may be less abundant in some groups,” said Slovis.
  • Some ethnicities, including Asians, have a genetic mutation in the enzyme called acetaldehyde dehydrogenase, which brings on rosy cheeks and a rapid heartbeat, even with a small amount of alcohol.

“Many can’t even drink to intoxication because they become flushed,” Dr. Michael Fingerhood, associate professor of medicine at Johns Hopkins University School of Medicine. “At such low levels they have such an effect.” Native Americans also metabolize alcohol much slower than many other ethnicities, said Slovis.

  1. related:
  2. quicklist: 3category: Handling Your Alcohol Consumptiontitle: Food url: text: Eating more is a surefire way to delay feeling drunk.
  3. “The more carbs and the more fat you consume, the more you’ll delay intoxication,” said Slovis.
  4. But that’s no excuse to drink more, said Slovis.
  5. “You’re not blocking the absorption, you’re just delaying so you don’t peak as quickly,” said Slovis.

In fact, the delayed intoxication can be confusing. Some might drink more than usual, and the combination of food and drink can make you more likely to get sick.

  • “You don’t appreciate how much you’ve had until it hits you,” said Slovis.
  • The higher the proof and the emptier the stomach, the stronger the effects.
  • related:
  • quicklist: 4category: Handling Your Alcohol Consumptiontitle: Timeurl: text: Many emergency rooms see the highest level of alcohol-related cases during the first weekend of the college semester.
  • “When you’re naive to alcohol, a little goes a very long way,” said Slovis.
  • Over time, regular consumers of alcohol are able to drink more without feeling the effects.
  • “Someone who drinks more over time will look less impaired at the same level of someone who drinks less frequently,” said Fingerhood.

Alcoholics are a prime example of how strong tolerance can be. Even if a person has quit drinking for decades, he or she can still drink to the amount they could before stopping without feeling any effects.

  1. “There’s memory for tolerance that we don’t understand,” said Fingerhood.
  2. related:
  3. quicklist: 5category: Handling Your Alcohol Consumptiontitle: Ageurl: text: While tolerance takes time to build, older age can take it away.

“Older people can be snowed by alcohol amounts that hardly touched them when they were younger,” said Dr. Peter Martin, director of the Division of Addiction Psychiatry at Vanderbilt University Medical Center.

  • Physical changes and changes in brain wiring as we age make it easier to feel the effects faster, said Martin.
  • For postmenopausal women, the changes in estrogen levels significantly slow alcohol metabolism, said Fingerhood.
  • related:
  • quicklist: 6category: Handling Your Alcohol Consumptiontitle: Genderurl: text:Premenopausal women are more likely to get drunk faster than men who drink the same amount of alcohol, said Fingerhood.

Body size and composition are obvious reasons for the difference. Men have more body water than women, which allow for wider distribution of alcohol throughout the body. Women have more fat than water weight, so alcohol is concentrated in a smaller volume, said Martin.

  1. Alcohol is also known to hit more women harder in the long run.
  2. Women are more prone to liver toxicity and all other complications from alcohol than men, said Martin.
  3. related:
  4. quicklist: 7category: Handling Your Alcohol Consumptiontitle: Perceptionurl: text: While perception doesn’t affect how drunk you really are, it can affect how drunk you feel.
  5. “Expectancy and previous experience do influence how people respond,” said Martin.

If some are told and believe there’s alcohol in a drink when in reality there isn’t, many might begin acting drunk even if they’re not, Martin said. Likewise, a person given alcohol but not told their drink is spiked might appear less drunk, he said.

  • Perhaps you felt that energy drinks or coffee got you back to functioning sooner.
  • “You get stimulated and might feel alert, but you’re not reasoning any better and you don’t have a quicker reaction time,” said Slovis.
  • It takes the same amount of time to detoxify with or without consuming stimulants like coffee, even though you may perceive yourself to be more sober.
  • related:

: 7 Reasons You’re Drunker Than Your Friends

How does alcohol affect the body based on weight?

How alcohol could cause weight gain – While the relationship between alcohol consumption and obesity remains unclear, there are good reasons to think that alcohol may play a role:

It stops your body from burning fat. It is high in kilojoules. It leads to greater hunger and less satiety (the feeling of being full). It can lead to cravings for salty and greasy foods.

Does the body burn alcohol before fat?

2. Alcohol is used as a primary source of fuel – There are also other elements that can cause weight gain outside of calorie content. When alcohol is consumed, it’s burned first as a fuel source before your body uses anything else. This includes glucose from carbohydrates or lipids from fats.

Why am I lightweight with alcohol?

Genetics could be the reason you’re a lightweight drinker, study says This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

  • If you’ve ever wondered why some people get drunk in an instant, the answer is genetics.
  • That’s according to,
  • They say a receptor in our brain affects our reaction to alcohol.
  • The protein receptor, located on cells in the cerebellum, is known as GABAA.

When it’s activated, it suppresses the firing of brain cells. That leads to balance issues, stumbling, slurred speech and reduced social inhibitions. Lightweights have receptors that overreact to even the smallest amount of alcohol. For others, the receptor takes a long time to be stimulated. This can lead to binge drinking and alcoholism.

  1. Researchers think increasing the receptor’s sensitivity could prevent people from drinking too much.
  2. “It takes them from drinking the equivalent of three to four units of alcohol in one to two hours, down to one to two units,” said David Rossi, a Washington State University assistant professor of neuroscience.
  3. The researchers believe therapy could be used to curb excessive drinking.
  4. They studied the information on mice.
  5. Those bred to have a sensitive receptor had trouble staying on a rotating cylinder after consuming the human equivalent of one or two drinks.
  6. Those bred to be desensitized could stay on after drinking three times as much alcohol.
  7. The study found those who got drunk quicker were more likely to stop drinking sooner.

“It mirrors the human situation,” said Rossi. “If you’re sensitive to the motor-impairing effects of alcohol, you don’t tend to drink much. If you’re not sensitive, you drink more.”

  • Researchers injected a drug called THIP into the cerebellum of the mice that were less sensitive alcohol.
  • The drug activates the GABAA receptor, mimicking what happens to those with alcohol-sensitive receptors.
  • It ended up deterring the mice from drinking.

Copyright 2023 Nexstar Media Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed. : Genetics could be the reason you’re a lightweight drinker, study says

What affects alcohol tolerance?

Factors That Influence Alcohol Tolerance – Your alcohol tolerance is affected by your drinking habits, genetics, overall health and gender. No one person is the same when it comes to how much alcohol their system can handle. There are a lot of factors at play including:

  • Genetics, gender and age
  • Frequency and amount of drinking
  • Your physical health
  • Family history of alcohol abuse

If you feel like your tolerance for alcohol is getting out of control, it’s time to get help. Treatment options include counseling, therapy and support groups like Alcoholics Anonymous

What can I eat to not get drunk fast?

Salmon can help replenish key nutrients and counteract inflammation – Salmon contains a ton of, an important nutrient that’s known to decrease with moderate to high alcohol consumption. The vitamin is essential for red blood cell production and nervous system functioning.

  1. The fishy superfood is also high in protein and healthy fats, both of which may slow the pace of alcohol absorption.
  2. In addition, can offset some of the inflammation in the brain and body that occurs due to heavy drinking.
  3. For a well-rounded pre-drinking meal, try cooking up some salmon with a side of asparagus.

The vegetable contains minerals and amino acids that are beneficial to liver health and may help, Top your toast will some healthy fats and protein. Westend61/Getty Images

What affects alcohol tolerance?

Factors That Influence Alcohol Tolerance – Your alcohol tolerance is affected by your drinking habits, genetics, overall health and gender. No one person is the same when it comes to how much alcohol their system can handle. There are a lot of factors at play including:

  • Genetics, gender and age
  • Frequency and amount of drinking
  • Your physical health
  • Family history of alcohol abuse

If you feel like your tolerance for alcohol is getting out of control, it’s time to get help. Treatment options include counseling, therapy and support groups like Alcoholics Anonymous

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Does more body fat make you more drunk?

Believe it or not, your body weight can have an affect on a Virginia DUI charge. This is because when a police officer takes a blood alcohol content (BAC) reading, the results will reflect the amount of alcohol within your body’s bloodstream, and the alcohol in your blood will be diluted by the water in your body.

  • Therefore, a person with a higher body mass (weight) may have more water in their body, which may dilute the alcohol in their blood.
  • A person with a lower body mass will generally have less water in their body, and hence more alcohol in their blood.
  • This means the BAC reading that led to your Virginia DUI should be questioned by a professional Virginia DUI attorney who can determine if your BAC test was correctly calculated for your body type.

A BAC reading can also be affected by a person’s body fat percentage. This is because fat holds much less water than muscle, and so it will absorb less alcohol from the blood. So if two people weigh the same, but one has more body fat, then after the same number of drinks the person with more body fat will have a higher BAC reading.

With the expert help of a Virginia DUI defense attorney, you may be able use this information to fight your DUI charge. If you have been arrested and charged with a Virginia DUI, then you may want to know how your body weight may have affected your BAC reading. To learn more, read our article: Your Body Weight and Your BAC Virginia DUI defense attorney Bob Battle has the experience and ability to help his clients use these errors to mount a successful DUI defense.

To learn more about Virginia DUI, get a free copy of Bob Battle’s consumer guide, How to Choose a DUI Lawyer in Virginia, Or, contact 804-673-5600 to schedule your legal consultation today.

Does body fat affect hangovers?

Hangovers Really Do Get Worse As We Get Older, And Here’s Why As the years go by, it gets harder to shake off the head-and-stomach-achey aftereffects of a night of drinking. Hangovers seem to get worse as we get older — and it’s not your imagination. It is, unfortunately, science.

We all know what a hangover is: Headaches, nausea, loss of appetite, diarrhea, shakiness or fatigue after drinking too much. The word practically defines itself: The medical term for “hangover” is “veisalgia,” which is from the Norwegian word “kveis” — which means “uneasiness following debauchery.” The weird thing is, scientists and doctors don’t totally understand what causes a hangover.

But we do know it’s a side effect of overwhelming the body with more alcohol than it can efficiently break down. Alcohol metabolism is a two-step process in the liver, where enzymes first break the alcohol down into acetaldehyde. “This toxin is probably the reason for a lot of the gross feelings that come with a hangover,” explains Dr.

  1. Rachel Vreeman, co-author of the book “Don’t Swallow Your Gum!” and assistant professor at the Indiana University School of Medicine.
  2. That’s because acetaldehyde is highly toxic – between 10 and 30 times more toxic than alcohol itself.
  3. The enzymes in your liver are next tasked with breaking down the acetaldehyde further, into a non-toxic substance called acetate.

But your liver can only metabolize about one drink per hour – so if you’re drinking more quickly than that, not all of the acetaldehyde gets broken down. In that case, the acetaldehyde is released into the blood stream to wreak havoc around your body, resulting in the awful feelings associated with a hangover.

  • There aren’t a lot of strong studies looking at how age affects the human body’s efficiency at breaking down alcohol, but a toxicology researcher in South Korea named Young Chul Kim has led studies looking at this process in aging rats.
  • He has a few theories on why hangovers are especially unbearable as we get older.

“Many factors appear to be involved in worsening of hangover in old age. One is that the liver capacity to cope with the toxicity of acetaldehyde decreases as we get old,” Kim said in an email. Acetaldehyde is directly detoxified in the liver by an antioxidant called glutathione.

“Our data indicated that, as age increases, glutathione generation capacity is decreased, so cells may not be recovered or repaired rapidly.” It’s just like everything else about us as we get older, points out Madelyn Fernstrom, diet and health editor for NBC News. “You can still do it, but you do it a little slower,” she says.

Another possible link between age and killer hangovers: We’ve gotten fatter. Or, thinner! Change in body size, in either direction, can potentially worsen a hangover. “When one’s body weight has increased, blood alcohol level decreases because of its wide distribution into body mass and fat, which leads one to drink extra glasses without realizing it, subsequently resulting in generation of more acetaldehyde,” Kim says.

Or when one’s body weight decreases, greater intoxication results due to limited distribution to the body after consumption of an equal amount of alcohol.” Older people also might be more likely to be on medications, or taking supplements, which may interfere with the metabolism of alcohol, experts say.

But experts agree that perhaps the most significant, if least scientific, explanation as to why hangovers feel so much worse when we get over is simply that we’re less likely to want to warrior through the headache and nausea, and much more likely to want to retreat to the couch until we feel better.

How can you increase your alcohol tolerance?

Alcohol and Tolerance – Alcohol Alert No.28-1995 National Institute on Alcohol Abuse and Alcoholism No.28 PH 356 April 1995 Alcohol and Tolerance Alcohol consumption interferes with many bodily functions and affects behavior. However, after chronic alcohol consumption, the drinker often develops tolerance to at least some of alcohol’s effects.

Tolerance means that after continued drinking, consumption of a constant amount of alcohol produces a lesser effect or increasing amounts of alcohol are necessary to produce the same effect (1). Despite this uncomplicated definition, scientists distinguish between several types of tolerance that are produced by different mechanisms.

Tolerance to alcohol’s effects influences drinking behavior and drinking consequences in several ways. This Alcohol Alert describes how tolerance may encourage alcohol consumption, contributing to alcohol dependence and organ damage; affect the performance of tasks, such as driving, while under the influence of alcohol; contribute to the ineffectiveness or toxicity of other drugs and medications; and may contribute to the risk for alcoholism.

Functional Tolerance Humans and animals develop tolerance when their brain functions adapt to compensate for the disruption caused by alcohol in both their behavior and their bodily functions. This adaptation is called functional tolerance (2). Chronic heavy drinkers display functional tolerance when they show few obvious signs of intoxication even at high blood alcohol concentrations (BAC’s), which in others would be incapacitating or even fatal (3).

Because the drinker does not experience significant behavioral impairment as a result of drinking, tolerance may facilitate the consumption of increasing amounts of alcohol. This can result in physical dependence and alcohol-related organ damage. However, functional tolerance does not develop at the same rate for all alcohol effects (4-6).

Consequently, a person may be able to perform some tasks after consuming alcohol while being impaired in performing others. In one study, young men developed tolerance more quickly when conducting a task requiring mental functions, such as taking a test, than when conducting a task requiring eye-hand coordination (4), such as driving a car.

Development of tolerance to different alcohol effects at different rates also can influence how much a person drinks. Rapid development of tolerance to unpleasant, but not to pleasurable, alcohol effects could promote increased alcohol consumption (7).

Different types of functional tolerance and the factors influencing their development are described below. During repeated exposure to low levels of alcohol, environmental cues and processes related to memory and learning can facilitate tolerance development; during exposure to high levels of alcohol, tolerance may develop independently of environmental influences.

Acute tolerance, Although tolerance to most alcohol effects develops over time and over several drinking sessions, it also has been observed within a single drinking session. This phenomenon is called acute tolerance (2). It means that alcohol-induced impairment is greater when measured soon after beginning alcohol consumption than when measured later in the drinking session, even if the BAC is the same at both times (8-10).

  1. Acute tolerance does not develop to all effects of alcohol but does develop to the feeling of intoxication experienced after alcohol consumption (4).
  2. This may prompt the drinker to consume more alcohol, which in turn can impair performance or bodily functions that do not develop acute tolerance.
  3. Environment-dependent tolerance.

The development of tolerance to alcohol’s eff ects over several drinking sessions is accelerated if alcohol is always administered in the same environment or is accompanied by the same cues. This effect has been called environment-dependent tolerance.

Rats that regularly received alcohol in one room and a placebo in a different room demonstrated tolerance to the sedative and temperature-lowering effects of alcohol only in the alcohol-specific environment (11). Similar results were found when an alcohol-induced increase in heart rate was studied in humans (12).

When the study subjects always received alcohol in the same room, their heart rate increased to a lesser extent after drinking in that room than in a new environment. Environment-dependent tolerance develops even in “social” drinkers in response to alcohol-associated cues.

  • In a study analyzing alcohol’s effects on the performance of an eye-hand coordination task, a group of men classified as social drinkers received alcohol either in an office or in a room resembling a bar.
  • Most subjects performed the task better (i.e., were more tolerant) when drinking in the barlike environment (13).

This suggests that for many people, a bar contains cues that are associated with alcohol consumption and promote environment-dependent tolerance. Learned tolerance. The development of tolerance also can be accelerated by practicing a task while under the influence of alcohol.

  1. This phenomenon is called behaviorally augmented (i.e., learned) tolerance.
  2. It first was observed in rats that were trained to navigate a maze while under the influence of alcohol (14).
  3. One group of rats received alcohol before their training sessions; the other group received the same amount of alcohol after their training sessions.
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Rats that practiced the task while under the influence of alcohol developed tolerance more quickly than rats practicing without prior alcohol administration. Humans also develop tolerance more rapidly and at lower alcohol doses if they practice a task while under the influence of alcohol.

  1. When being tested on a task requiring eye-hand coordination while under the influence of alcohol, people who had practiced after ingesting alcohol performed better than people who had practiced before ingesting alcohol (15).
  2. Even subjects who only mentally rehearsed the task after drinking alcohol showed the same level of tolerance as those who actually practiced the task while under the influence of alcohol (15).

The expectation of a positive outcome or reward after successful task performance is an important component of the practice effect on tolerance development. When human subjects knew they would receive money or another reward for successful task perfmance while under the influence of alcohol, they developed tolerance more quickly than if they did not expect a reward (16).

  • The motivation to perform better contributes to the development of learned tolerance.
  • Learned and environment-dependent tolerance have important consequences for situations such as drinking and driving.
  • Repeated practice of a task while under the influence of low levels of alcohol, such as driving a particular route, could lead to the development of tolerance, which in turn could reduce alcohol-induced impairment (16).

However, the tolerance acquired for a specific task or in a specific environment is not readily transferable to new conditions (17,18). A driver encountering a new environment or an unexpected situation could instantly lose any previously acquired tolerance to alcohol’s impairing effects on driving performance.

  1. Environment-independent tolerance.
  2. Exposure to large quantities of alcohol can lead to the development of functional tolerance independent of environmental influences.
  3. This was demonstrated in rats that inhaled alcohol vapors (19).
  4. In another study, mice demonstrated tolerance in environments different from the one in which the alcohol was administered (20).

Significantly larger alcohol doses were necessary to establish this environment-independent tolerance than to establish environment-dependent tolerance (20) Metabolic Tolerance Tolerance that results from a more rapid elimination of alcohol from the body is called metabolic tolerance (2).

It is associated with a specific group of liver enzymes that metabolize alcohol and that are activated after chronic drinking (21,22). Enzyme activation increases alcohol degradation and reduces the time during which alcohol is active in the body (2), thereby reducing the duration of alcohol’s intoxicating effects.

However, certain of these enzymes also increase the metabolism of some other drugs and medications, causing a variety of harmful effects on the drinker. For example, rapid degradation of sedatives (e.g., barbiturates) (23) can cause tolerance to them and increase the risk for their use and abuse.

  1. Increased metabolism of some prescription medications, such as those used to prevent blood clotting and to treat diabetes, reduces their effectiveness in chronic drinkers or even in recovering alcoholics (24).
  2. Increased degradation of the common painkiller acetaminophen produces substances that are toxic to the liver (25) and that can contribute to liver damage in chronic drinkers.

Tolerance and the Predisposition to Alcoholism Animal studies indicate that some aspects of tolerance are genetically determined. Tolerance development was analyzed in rats that were bred to prefer or not prefer alcohol over water (26,27). The alcohol-preferring rats developed acute tolerance to some alcohol effects more rapidly and/or to a greater extent than the nonpreferring rats (26).

  • In addition, only the alcohol-preferring rats developed tolerance to alcohol’s effects when tested over several drinking sessions (27).
  • These differences suggest that the potential to develop tolerance is genetically determined and may contribute to increased alcohol consumption.
  • In humans, genetically determined differences in tolerance that may affect drinking behavior were investigated by comparing sons of alcoholic fathers (SOA’s) with sons of nonalcoholic fathers (SONA’s).

Several studies found that SOA’s were less impaired by alcohol than SONA’s (28,29). Other studies found that, compared with SONA’s, SOA’s were affected more strongly by alcohol early in the drinking session but developed more tolerance later in the drinking session (30).

These studies suggest that at the start of drinking, when alcohol’s pleasurable effects prevail, SOA’s experience these strongly; later in the drinking session, when impairing effects prevail, SOA’s do not experience these as strongly because they have developed tolerance (30). This predisposition could contribute to increased drinking and the risk for alcoholism in SOA’s.

Alcohol and Tolerance-A Commentary by NIAAA Director Enoch Gordis, M.D. Tolerance can be a useful clue for clinicians in identifying patients who may be at risk for developing alcohol-related problems. For example, younger patients who are early in their drinking histories and who report that they can “hold their liquor well” may be drinking at rates that will place them at risk for medical complications from alcohol use, including alcoholism.

The fact that tolerance to all of alcohol’s effects does not develop simultaneously is also important; people who are mildly tolerant may exhibit more symptoms of impairment when faced with unfamiliar activities, such as driving in an unknown area, than when they are engaged in routine actions, such as driving home from work.

Lastly, although we know that initial sensitivity to alcohol may play a role in the development of alcoholism, the role of tolerance in maintaining addiction to alcohol needs further exploration. References (1) American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition.

Washington, DC: the Association, 1994. (2) Tabakoff, B.; Cornell, N.; & Hoffman, P.L. Alcohol tolerance. Annals of Emergency Medicine 15(9):1005-1012, 1986. (3) Chesher, G., & Greeley, J. Tolerance to the effects of alcohol. Alcohol, Drugs and Driving 8(2):93-106, 1992. (4) Vogel-Sprott, M.D. Acute recovery and tolerance to low doses of alcohol: Differences in cognitive and motor skill performance.

Psychopharmacology 61(3):287-291, 1979. (5) Pohorecky, L.A.; Brick, J.; & Carpenter, J.A. Assessment of the development of tolerance to ethanol using multiple measures. Alcoholism: Clinical and Experimental Research 10(6):616-622, 1986. (6) Tabakoff, B., & Kiianmaa, K.

  1. Does tolerance develop to the activating, as well as the depressant, effects of ethanol? Pharmacology Biochemistry & Behavior 17(5):1073-1076, 1982.
  2. 7) Tabakoff, B., & Hoffman, P.L.
  3. Tolerance and the etiology of alcoholism: Hypothesis and mechanism.
  4. Alcoholism: Clinical and Experimental Research 12(1):184-186, 1988.

(8) Beirness, D., & Vogel-Sprott, M. The development of alcohol tolerance: Acute recovery as a predictor. Psychopharmacology 84(3):398-401, 1984. (9) Bennett, R.H.; Cherek, D.R.; & Spiga, R. Acute and chronic alcohol tolerance in humans: Effects of dose and consecutive days of exposure.

Alcoholism: Clinical and Experimental Research 17(4):740-745, 1993. (10) Hiltunen, A.J., & Järbe, T.U.C. Acute tolerance to ethanol using drug discrimination and open-field procedures in rats. Psychopharmacology 102(2):207-212, 1990. (11) Mansfield, J.G., & Cunningham, C.L. Conditioning and extinction of tolerance to the hypothermic effect of ethanol in rats.

Journal of Comparative and Physiological Psychology 94(5):962-969, 1980. (12) Dafters, R., & Anderson, G. Conditioned tolerance to the tachycardia effect of ethanol in humans. Psychopharmacology 78(4):365-367, 1982. (13) McCusker, C.G., & Brown, K. Alcohol-predictive cues enhance tolerance to and precipitate “craving” for alcohol in social drinkers.

Journal of Studies on Alcohol 51(6):494-499, 1990. (14) LeBlanc, A.E.; Gibbins, R.J.; & Kalant, H. Behavioral augmentation of tolerance to ethanol in the rat. Psychopharmacologia 30:117-122, 1973. (15) Vogel-Sprott, M.; Rawana, E.; & Webster, R. Mental rehearsal of a task under ethanol facilitates tolerance.

Pharmacology Biochemistry & Behavior 21(3):329-331, 1984. (16) Sdao-Jarvie, K., & Vogel-Sprott, M. Response expectancies affect the acquisition and display of behavioral tolerance to alcohol. Alcohol 8(6):491-498, 1991. (17) Siegel, S., & Sdao-Jarvie, K.

Attenuation of ethanol tolerance by a novel stimulus. Psychopharmacology 88(2):258-261, 1986. (18) Tsibulsky, V.L., & Amit, Z. Role of environmental cues as Pavlovian-conditioned stimuli in enhancement of tolerance to ethanol effects: 1. Lethal effects in mice and rats. Pharmacology Biochemistry & Behavior 45(2):473-479, 1993.

(19) Tabakoff, B., & Culp, S.G. Studies on tolerance development in inbred and heterogeneous stock National Institutes of Health rats. Alcoholism: Clinical and Experimental Research 8(5):495-499, 1984. (20) Melchior, C.L., & Tabakoff, B. Modification of environmentally cued tolerance to ethanol in mice.

Journal of Pharmacology and Experimental Therapeutics 219(1):175-180, 1981. (21) Lieber, C.S. Metabolism of ethanol and associated hepatotoxicity. Drug and Alcohol Review 10(3):175-202, 1991. (22) Lieber, C.S. The microsomal ethanol oxidizing system: Its role in ethanol and xenobiotic metabolism. Biochemical Society Transactions 16(3):232-239, 1988.

(23) Misra, P.S.; Lefèvre, A.; Ishii, H.; Rubin, E.; & Lieber, C.S. Increase of ethanol, meprobamate and pentobarbital metabolism after chronic ethanol administration in man and in rats. American Journal of Medicine 51(3):346-351, 1971. (24) Lieber, C.S.

Interaction of ethanol with other drugs. In: Lieber, C.S., ed. Medical and Nutritional Complications of Alcoholism: Mechanisms and Management. New York: Plenum Press, 1992. pp.165-183. (25) Sato, C.; Matsuda, Y.; and Lieber, C.S. Increased hepatotoxicity of acetaminophen after chronic ethanol consumption in the rat.

Gastroenterology 80(1):140-148, 1981. (26) Waller, M.B.; McBride, W.J.; Lumeng, L.; & Li, T.-K. Initial sensitivity and acute tolerance to ethanol in the P and NP lines of rats. Pharmacology Biochemistry & Behavior 19(4):683-686, 1983. (27) Lê, A.D., & Kiianmaa, K.

Characteristics of ethanol tolerance in alcohol drinking (AA) and alcohol avoiding (ANA) rats. Psychopharmacology 94(4):479-483, 1988. (28) Schuckit, M.A. Ethanol-induced changes in body sway in men at high alcoholism risk. Archives of General Psychiatry 42(4):375-379, 1985. (29) Schuckit, M.A., & Gold, E.O.

A simultaneous evaluation of multiple markers of ethanol/placebo challenges in sons of alcoholics and controls. Archives of General Psychiatry 45(3):211-216, 1988. (30) Newlin, D.B., & Thomson, J.B. Alcohol challenge with sons of alcoholics: A critical review and analysis.

  1. Psychological Bulletin 108(3):383-402, 1990.
  2. ACKNOWLEDGMENT: The National Institute on Alcohol Abuse and Alcoholism wishes to acknowledge the valuable contributions of Boris Tabakoff, Ph.D., professor and chairman of the Department of Pharmacology, University of Colorado School of Medicine, Denver, CO, to the development of this Alcohol Alert.

All material contained in the Alcohol Alert is in the public domain and may be used or reproduced without permission from NIAAA. Citation of the source is appreciated. Copies of the Alcohol Alert are available free of charge from the Scientific Communications Branch, Office of Scientific Affairs, NIAAA, Willco Building, Suite 409, 6000 Executive Boulevard, Bethesda, MD 20892-7003.