Alcohol and Health: Why is Increased Tolerance to Alcohol Harmful?
A deep dive into tolerance and why it is often misunderstood
In my previous post, “What is the Definition of a Drinking Problem”, one of the indicators was tolerance which generally is defined as needing more alcohol to get the same effect. What I have found in both my research and clinical work is how frequently tolerance is misunderstood. If you ask a health care provider and a college student if tolerance to alcohol is helpful or harmful, you will most likely get different answers. This week we are focusing on tolerance—what it is, why it is problematic, and how to address it.
Let’s start with an example of tolerance. Meet Caden and John. Both are 22 year-old males who have the same build and weight, however they have different drinking patterns.
Caden is a recent college graduate and has spent the past 4 years in a fraternity. He considers himself a “seasoned drinker” and is proud of the fact he can hold his alcohol well. He typically drinks 4 days or more a week and attends parties or gatherings on the weekends. He drinks around 10 drinks on Friday and Saturday nights (usually 5 beers and 5 shots). He has been known to drink more than that on weekends that involve a big celebration, holiday, or football game. On other drinking days he drinks less, around 5 drinks so it doesn’t interfere with other responsibilities. When Caden first started drinking he used to feel intoxicated after drinking half the amount he currently consumes, however over time he could drink more without feeling drunk so easily. He used to experience hangovers regularly (among other physical symptoms), however over the past few years he noticed he is able to bounce back from heavy episodes faster. He sees this as a positive since he is able to recover quickly and drink on consecutive days.
John also recently graduated from college and considers himself to be a light and social drinker. John drinks about 2 days per week, usually on Friday and nights when he hangs out with friends. He typically drinks 2-3 beers per occasion, although about once every few months he has been known to engage in a heavy drinking and consume about 8-10 drinks. This usually happens if he plays a drinking game, or is out longer than planned. John reports he usually feels highly intoxicated, has experienced consequences such as a blackout and feels very hungover the next day. After these experiences he usually takes a break from drinking for a couple of weeks. Overall, John has maintained a fairly consistent drinking pattern since the end of his freshman year. For the most part John tries to avoid the negative effects of alcohol since he enjoys feeling a slight buzz, but does not like recovering from nights of heavy alcohol use.
Based on this example, it isn’t hard to see why tolerance can often be perceived as a positive depending on your drinking goals. Individuals who can “hold their liquor well” are often respected by their peers. Tolerance allows individuals to drink the same amount of alcohol without feeling the same effects and over time, increase their consumption. It also influences the body’s ability to handle consequences associated with drinking more efficiently meaning consequences related to drinking become milder (e.g., hangovers, vomiting, etc.). While some may see not experiencing a hangover after a night of heavy drinking as a positive, in reality it can be helpful. Hangovers often provide feedback to individuals when they have overdone it and may provide an opportunity to take a break from drinking in the short term or change our patterns.
This specific type of tolerance is known as functional tolerance. Functional tolerance occurs when an individual’s brain adapts and compensates for the effects alcohol has on the body. Two important things to note about functional tolerance:
As functional tolerance increases, people who are intoxicated don’t necessarily appear so. What we find is that individuals’ with high blood alcohol concentration (BAC) don’t feel drunk and may not act like it. For example, if Caden and John (who both weigh 175 pounds) drank 6 drinks over 2 hours they would most likely feel and behave very differently even thought their BAC is exactly the same. Just because someone might feel less intoxicated doesn’t mean they are less intoxicated. There are 4 factors that determine intoxication: 1. number of standard drinks consumed (for a refresher on standardized drinks you can revisit this post), 2. time taken to consume, 3. gender, and 4. body weight. We can use a bac calculator to compute our actual BAC. In this case, both John and Caden’s BACs are 0.13%. They are both over the limit of legal intoxication (.08) and it will take around 9 hours for alcohol to completely clear their system. Typical effects associated with this BAC are boisterousness, possibility of nausea and vomiting, and feeling hung over the next day.
Tolerance can be environmentally specific. Humans are creatures of habit. As our brain adapts to functioning under the influence of alcohol it does so more effectively when we are in a familiar environment. If an individual tends to drink in the same locations or drive after drinking they will be able to navigate and function more easily in those locations after developing tolerance. However if they drink in a new location (e.g., go on vacation, new bar, etc.), they may feel the effects of alcohol more strongly. As you can imagine, being intoxicated in a strange place or driving an unfamiliar route after drinking can easily increase the risk of something bad happening.
Why is tolerance risky and/or harmful?
Higher tolerance leads to drinking more alcohol. This puts a lot of strain on the body and organs—namely the liver. Not only is the liver responsible for processing alcohol, it also is a key player in processing other toxins and medications. Alcohol takes a toll on other organs (e.g., brain) and our overall health as well. It is not uncommon for individuals with high tolerance to reach dangerous BACs (e.g., .30-.40 and higher) which can be lethal.
Drinking larger amounts of alcohol increases risk of developing physical dependency on alcohol over time. Tolerance is often sneaky. It can increase quickly with frequent and heavy drinking or it can gradually progress over months or several years. Over time, consuming larger amounts of alcohol over sustained periods of time can lead to chronic patterns of alcohol use and the body needing alcohol to function. In the examples presented of Caden and John they were young adults. However they have established drinking patterns that will continue as they age unless they decide to modify them. While some young adults decrease their drinking as they enter different stages of life, others don’t. How do you imagine they might be functioning in 5, 10, 20 years from now? It isn’t hard to picture Caden having a problematic relationship with alcohol unless he reduces his drinking along the way.
Underestimating intoxication. Individuals with a higher tolerance may not feel intoxicated even though they are. This means they may make decisions to drive (or engage in other decisions) when they should not. Certain skills such as reaction time are often still impaired when intoxicated even if tolerance is present. Tolerance doesn’t allow individuals to operate a vehicle safely when they are legally intoxicated. Remember, tolerance has no impact on BAC.
TIPS for reducing tolerance:
Reflect on how your drinking may have changed. Has your drinking crept up over the years? Maybe you noticed a recent spike in consumption. If you feel like you are able to drink more alcohol before feeling the effects (e.g., buzzed, intoxicated) your tolerance has likely increased. The good news is we can reduce our tolerance.
Take a break from alcohol. If you feel you have an increased tolerance to alcohol taking a break from drinking will allow your body to reset. The general recommendation is 30 days will reduce tolerance, however everyone is different. It is important to note that if you do take a break, you will be more sensitive to the effects of alcohol when you resume drinking.
Focus on BAC, not how you feel. Since tolerance interferes with our ability to accurately assess our BAC, it’s important to use external data (number of standard drinks consumed, time taken to consume, weight, gender) rather than internal sensations to estimate intoxication. Research, including some of my own studies, have shown that individuals who tend to drink more heavily compared to their peers (and have higher tolerance) and rely on how they feel rather than external data make more underestimation errors when assessing personal levels of intoxication. BAC calculators are a great tool to use to better understand personal limits and are easy to access online or via smartphone apps (e.g. IntelliDrink).
Set limits to prevent tolerance. The best way to prevent tolerance is to set and maintain personal limits. This may include not drinking daily, consuming 1-2 drinks per occasion, which is consistent with NIH guidelines.
In terms of our health and well-being, drinking large quantities of alcohol isn’t beneficial. Not only does alcohol take a toll on our health, it becomes more expensive, can interfere with goals and responsibilities, and results in consuming additional calories/weight gain. For those who choose to drink alcohol, using a “less is more” approach is optimal. If you would like to learn more technical and specific information about tolerance, NIAAA provides a nice overview you can access here.