Alcohol and the Human Body 101

Any attorney who successfully fights California DUI / DWI charges is well-versed in how alcohol affects the human body. Although every individual metabolizes alcohol differently - the rate depends on factors that include weight, gender, metabolic rate, etc. - the basic process is the same for everyone. The skilled defense attorneys from The Kavinoky Law Firm have the knowledge needed to analyze the factors in a specific case to challenge chemical tests and craft a successful defense.

Many drivers are unaware that alcohol is a central nervous system depressant. How much the central nervous system function is impaired is directly proportionate to the concentration of alcohol in the blood.

There are three stages of alcohol metabolism: Absorption, distribution, and elimination.

Absorption is the phase when alcohol enters the body, and then the bloodstream, and is distributed throughout the body. Alcohol is not digested like other ingested substances - it is absorbed unchanged directly through the stomach lining. Because of its large surface area, the small intestine absorbs much more alcohol than the stomach, which has a far smaller surface area.

As the alcohol is absorbed, the individual's blood alcohol content (BAC) rises until it reaches a peak concentration, then gradually tapers off. It generally takes 30 to 60 minutes to reach peak alcohol levels after an individual stops drinking.

Once the alcohol is absorbed by the gastrointestinal tract, it enters the bloodstream and is distributed through all of the body's water-containing components. Because it is distributed so quickly and thoroughly, alcohol affects the central nervous system even in small concentrations.

Alcohol is distributed to bodily tissues by the bloodstream. Veins carry the blood to and through the lungs where the blood becomes oxygenated. Arteries then carry the oxygen-rich blood to the brain and the rest of the body. Alcohol is completely soluble in water, so BAC is directly proportional to total body water content. Water content varies from person to person.

Generally speaking, the less an individual weighs, the more he or she will be affected by alcohol. This is because smaller people have less water in their bodies than larger people. For people of the same weight, a well-muscled individual will be less affected than someone with a higher percentage of fat, since fatty tissue does not contain very much water and will not absorb very much alcohol.

In general, women are more affected by alcohol consumption than men, because women's bodies typically have more fat and less water in their bodies. About 68 percent of a man's body weight is water, while only about 55 percent of a woman's body is water weight.

The body begins to eliminate alcohol through metabolism, excretion, and evaporation approximately 15 to 45 minutes after a person consumes his or her last drink. Metabolism, which occurs in the liver, accounts for approximately 95 percent of alcohol elimination. An individual generally metabolizes one average drink, or five ounces of alcohol, per hour.

In addition to gender, body weight, and other factors affecting metabolic rates, there are several additional issues that affect alcohol metabolism. Individuals who are in good health metabolize alcohol more efficiently than unhealthy people. Chronic alcoholics whose livers function properly metabolize alcohol more quickly than the average person. Younger people process alcohol more efficiently than older people.

Excretion and evaporation eliminate a small amount of alcohol from the body. Alcohol is excreted unchanged through urine, tears, sweat, semen, and saliva. Excretion is typically responsible for the smell of alcohol detectable on individuals who have been drinking. Alcohol evaporates from the blood into the lungs and is excreted in breath, allowing it to be measured in a breath sample.

Alcohol elimination rates are inversely proportional to alcohol concentration in the blood. This means that the higher the blood alcohol levels, the slower the rate of elimination.

Although alcohol is excreted in the breath, not all of the air that comes from the lungs is equal in alcohol concentration. The highest concentration comes at the end of a long exhalation of breath, where the air was in closest proximity to the blood. This is why police tell drivers to blow long and hard during breath testing, because the deep lung air will have the highest concentrations of alcohol, and result in the highest BAC.

Eating before drinking or consuming food and alcohol together also affects the amount of alcohol in the bloodstream. Food in the stomach affects the absorption of alcohol by the small intestine, so the more an individual has in his or her stomach while drinking, the lower the BAC. A valve at the bottom of the stomach closes when there is food in the stomach and prevents alcohol from reaching the small intestine. This causes the alcohol in the stomach to be absorbed at a slower rate, which affects the distribution into the bloodstream, and ultimately the rate of elimination.

Although many factors influence an individual's alcohol metabolism, police and prosecutors don't always take these issues into consideration when considering a drunk driving charge. An individual's alcohol metabolism rate is of key importance in a drinking and driving case, because chemical tests typically take place an hour or more after police stop a driver, and the person's BAC at the time of driving must be estimated.

A qualified California attorney with experience defending DUI / DWI cases can use these factors to a driver's advantage, and successfully fight a drunk driving case.