We’re all aware that the more we drink, the “better” we get at it. AKA, the more we can drink without really getting drunk. It’s something many across society see as a badge of honour, but that’s a very dangerous game to be playing.
Tolerance builds over time, with heavy drinkers often numbed to the effect. In fact, visit anyone in a rehab going through alcohol detoxification and you’ll see high levels of tolerance after years of abuse.
Understanding alcohol tolerance can be really valuable when it comes to addressing a relationship with the substance, so here’s all you should know about the science behind alcohol tolerance…
What is alcohol tolerance?
Let’s start with what alcohol tolerance actually is. Essentially, this refers to the reduced effect alcohol has on the body when it is consumed. Generally, it works that the more someone drinks, the less of an effect alcohol will have. So, for example, if you were to drink the same number of pints over time, that would once leave you tipsy, eventually that wouldn’t have much of an effect.
That doesn’t mean that your body processes alcohol faster, which is a common misconception, but more that it reflects the changes in the way the brain and body responds. Where the danger comes in is the misleading nature of tolerance. While a person may not feel drunk, their blood alcohol concentration could still be high and as a result there is a risk of harm, whether that be through accidents or long-term organ damage.
The role of the liver
The liver plays a big part in tolerance to alcohol, as it is primarily metabolised by the organ. Alcohol dehydrogenase breaks the ethanol down into acetaldehyde, a compound which is then further processed into acetic acid and then water and carbon dioxide.
However, with repeated drinking, the liver increases production of ADH to build tolerance and as a result clear the alcohol slightly faster. However, the by-products of alcohol metabolism are particularly harmful and can contribute to liver disease.
The brain’s adaptation
Perhaps the bigger changes that can happen in regards to tolerance are in the brain. When we drink booze, brain activity slows down, which can leave us feeling relaxed, as well as reducing inhibitions and impairing coordination.
That’s because alcohol acts as a depreassant, enhancing the effect of gamma-aminobutyric acid (GABA). With more frequent drinking, the brain compensates and reduces sensitivity to GABA and increases the excitatory, glutamate. This means that a greater amount of booze is needed to have the same, sedative effects.
This can also be a factor in experiencing withdrawal symptoms when stopping drinking, with too little GABA and too much glutamate leading to the likes of anxiety, tremors and in some cases, seizures.
Types of alcohol tolerance
Scientists recognise several distinct types of tolerance:
- Acute tolerance: Effects diminish within a single drinking session. A person may feel less intoxicated after a few hours even though their BAC remains high.
- Metabolic tolerance: The liver processes alcohol more efficiently with repeated use.
- Functional tolerance: The nervous system adapts to the presence of alcohol, reducing its effects.
- Behavioural tolerance: People learn to compensate for impairment, for example by concentrating harder on tasks when drunk, which can give the illusion of sobriety.
Genetics and individual differences
In some cases, genetics can also play a part in tolerance to alcohol too. Genetic coding can vary how efficiently alcohol is broken down. For example, in some East Asian populations, tolerance can be lower as typically people carry a variant of aldehyde dehydrogenase that has a lower tolerance, as well as leaving people feeling nauseous and having facial flushing.
Factors such as weight, sex and overall health can also play a part, with women typically experiencing stronger effects from alcohol compared to men as a resuly of body composition and enzyme activity.
The risks of high tolerance: Don’t wear it as a badge of honour
While we may think it’s cool to be able to handle our drink, that is a dangerous mentality to have.
High tolerance often encourages heavier drinking, increasing the likelihood of liver damage, cardiovascular disease, and certain cancers. Tolerance does not protect against alcohol poisoning: even if someone feels sober, their blood alcohol levels may still be lethal.
