The Biology of Intoxication

introduction to biology of intoxication

Introduction to the Biology of Intoxication

What is Intoxication Exactly?

introduction to biology of intoxicationDriving under the influence of alcohol is prohibited by law in all 50 states, with varying degrees of what is an acceptable blood alcohol concentration – but why is that? We know that alcohol causes physical and mental impairments but generally people do not understand the actual biology behind intoxication. Even though there is a legal limit for alcohol consumption for a person driving, even a small amount of alcohol can begin to affect your body – and sometimes in ways that you may not even notice until it is too late.

To begin with, intoxication is actually defined as poisoning or the state of being poisoned.[i] Even though drinking alcohol is a legally permissive act – it is still poisoning your body. Even so, drinking has been a socially acceptable practice for tens of thousands of years.[ii] Intoxication is a result of alcohol entering the bloodstream faster than the liver can breakdown the ethanol into non-intoxicating byproducts.[iii] In layman’s terms – there is only so much alcohol you can fill your liver with before it needs to find somewhere else to go. If this occurs, the liver has not yet had the chance to make that alcohol non- intoxicating.

The liver is only able to metabolize alcohol at a normal rate of 50 milliliters for every 90 minutes.[iv]  50 milliliters is just 2 ounces of fluid, which is roughly ¼ a cup. That is not a lot of fluid, certainly less than an average alcoholic drink. So what happens when your body ingests more than those 50 milliliters? First off, alcohol passes through your gastrointestinal tract (stomach, intestines, colon, etc.) and about 20 to 25 percent of the alcohol content is absorbed into the stomach, while the remaining percentage is absorbed in the small intestines.[v] The alcohol is then transported through a vein directly from the small intestines to the liver, where the liver can start breaking down that maximum 50 milliliter amount per 90 minutes. Note that it is possible for a person’s liver to metabolize alcohol at a faster rate than 90 minutes per 50 milliliters – it is also possible for a person’s liver to metabolize alcohol at a slower rate. If you drink more than that 50 milliliter amount, the remaining alcohol content will then enter into your bloodstream.[vi] Your brain will absorb excess alcohol through the bloodstream within only 5 minutes of ingestion.[vii]

Immediate Effects of Intoxication on the Body

Hombre con problema de adiccin al alcohol - entregando la llaves.Depending on how much you drank and how fast your body metabolizes alcohol will determine when your peak blood alcohol concentration is achieved – but that typically ranges from 30 to 90 minutes after drinking.[viii] However, once alcohol reaches the brain through the blood stream, the body will start to feel the effects of the intoxication very quickly. Some of the noticeable effects include: slowed reaction times, reduced inhibition and increased impulsivity, poor memory, difficulty thinking and concentration.[ix] Some of the more intense effects that a person will start to notice pretty quickly include: blackouts – where you do not remember what happened, slurred speech, blurred vision, difficulty walking and balancing, mood swings and extreme emotions, and slowed heart rate and breathing.[x]

So, what do these immediate effects from alcohol have on a person’s ability to drive? A person’s cognitive abilities and motor skills are crucial for a person to operate a motor vehicle, of any kind, and a reduction in those skills as a result of drinking is a dangerous combination. Drinking also reduces a person’s inhibitions, which could result in a person not wearing their seatbelt while driving, or increase the chances the driver will speed while driving.[xi] For ever drink a person has, the risk of accidents increases.

There are also a lot of hidden effects of drinking alcohol that can arise pretty quickly after drinking. Excessive alcohol can upset the lining of your stomach, and actually result in diarrhea.[xii] Alcohol can cause irregular heartbeats, increase blood pressure, and even cause heart failure.[xiii] Alcohol can also affect your immune system, which makes you much more susceptible to infections and disease.[xiv] When alcohol starts to interrupt your immune system, a protein in your lung responsible for keeping fluid out is disrupted and can lead to respiratory infections.[xv] A person who is feeling unwell may also have impairments to their driving, depending on the severity. A person who has been drinking, and is feeling unwell from the drinking can create a dangerous combination.

When do These Affects Start to take Place?

the biology of intoxication and when the effects take placeAgain, depending on how your body metabolizes alcohol will depict how much alcohol is necessary for various levels of impairment. Generally, though there is a range that is based on blood alcohol concentration. At 0.001% to 0.029% an average person will appear to be behaving normally but subtle effects could be detected with specialized testing.[xvi] At 0.030% to 0.059% a person may appear to be relaxed and talkative but they will experience an impairment with their concentration.[xvii] At 0.060% to 0.099% the person will have blunted feelings, reduced sensitivity to pain and be more extroverted than normal.[xviii] At this point, the body will be impaired to reasoning, depth perception, peripheral vision, and glare recovery.[xix] It is at this bracket level of blood alcohol concentration that the law deems a person to be unfit to drive. The legal limit set across the nation, in every state, is 0.08% blood alcohol concentration.[xx] It makes sense that at 0.08% the law says “no” to driving. Impairment of depth perception may make a driver believe that a car down the street is 100 feet away, when the car is really only 50 feet away – giving the driver a false sense of security when it comes to turning.

As the blood alcohol concentration increases, the impairment and behavior becomes much more extreme. When the blood alcohol content reaches 0.200% to 0.299%, there is a possibility of a person passing out and experiencing memory blackout.[xxi] At a blood alcohol concentration of 0.400% to 0.500% the possibility of death starts to creep in and at a blood alcohol concentration of anything above 0.500% there is a high possibility of death.[xxii]

Blood Alcohol Concentration and DUIs

blood alcohol consumption and the biology of intoxicationNow, even though the legal limit in every state for drinking and driving is having a blood alcohol concentration of 0.08% – this does not mean that if you have a blood alcohol concentration below the legal limit that you are in the clear. So, if a person is pulled over to appearing to be impaired and their blood alcohol concentration is at 0.079% – that person cannot laugh at the office and driver away. If an office believes that a person is impaired to the “slightest degree” that person can receive a DUI – even if their blood alcohol concentration is at 0.02% or lower.[xxiii]

The decision is up to the police office, and the police officer does not rely solely on the blood alcohol concentration reading alone.[xxiv]  The officer can make an arrest based off whether the driver was weaving or speeding as a result of impaired judgment, there is a smell of alcohol on the driver’s breath, or if there is alcohol in the vehicle.[xxv] The officer will even take note of how the driver produces documentation, how the driver exists the vehicle, or if the driver has difficulty performing the roadside balancing tests.[xxvi] A person may believe that they are not impaired after a few drinks, but when they go to pull out their insurance card – they may fumble around and not be able to compose themselves as quickly as if they had nothing to drink that night. Granted, some people are just clumsy – so there is a lot of discretion with the police officer to determine if the driver has been drinking, or if they are just a klutz.


Drinking has been a societal norm for as long as people have been able to ferment fruits and barley. Even though drinking is actually poisoning the body, it is incredibly common among people today to drink on a regular basis. While some religions prohibit drinking, some religions even include drinking in their service. Understanding how your body reacts and metabolizes alcohol could be the difference between life and death, or freedom and imprisonment when it comes to drinking and driving. The standard DUI is given when a person’s blood alcohol concentration is above 0.08%, and this is a national standard. While it is good that there is a national standard to adhere to, the way in which alcohol affects the body still greatly ranges. In some people, once their blood alcohol concentration is at or above 0.08%, they may not even have many of the delayed reactions and impairments that alcohol gives a standard person. On the flip side, another person may be unable to walk in a straight line once their blood alcohol concentration is at or above 0.08%.

So even though the law is set for people to be permitted to drive while intoxicated up to 0.08%, drinking and driving is still a very discretionary process. After a person has been drinking for even just a few weeks, they can typically decide how impaired they are – to some degree. Some people may know that two 16 ounce beers will allow them to drive home without drastic impairment, and without breaking the law. But that same person may know that two shots of whiskey may put them over the edge. Understanding how your body functions with alcohol will not only allow you to act more responsibly, it’ll keep

[i] See Intoxication. Biology Online: Answers to all your biology questions. (Accessed April 29, 2016).

[ii] See History of Drinking Around the World. Alcohol: Problems and Solutions. (Accessed April 29, 2016).

[iii] See Alcohol Metabolism: An Update. National Institute on Alcohol Abuse and Alcoholism. (Accessed April 29, 2016).

[iv] Id.

[v] See Anne Fox, PhD. Expressions of Drunkenness (Four Hundred Rabbits) (ICAP Series on Alcohol in Society). (Published September 9, 2010).

[vi] Id at 13.

[vii] Id at 14.

[viii] Id at 15.

[ix] See Short-term Effects of Drinking. Better Health Channel. (Accessed April 29, 2016).

[x] Id.

[xi] Id.

[xii] Id.

[xiii] Id.


[xv] Id.

[xvi] See Alcohol and Flying. Flight (Accessed April 29, 2016).

[xvii] Id.

[xviii] Id.

[xix] Id.

[xx] See Comparing State DUI Law. (Accessed April 29, 2016).

[xxi] See Alcohol and Flying. Flight (Accessed April 29, 2016).

[xxii] Id.

[xxiii] See DUI Citations Issued Even When BAC Below Legal Limit. Rosenstein Law Group. (Accessed April 29, 2016).

[xxiv] Id.

[xxv] Id.

[xxvi] Id.