According to the National Institutes of Health and the American Medical Association, about a dozen variables go into the mix: body weight; amount of muscles or fat; gender; age; other chemicals in drinks; speed of drinking; food in the stomach; drinking history; tolerance to alcohol; other drugs in your system; general health; and emotional state. Alcohol (ethanol) is usually absorbed from the gastrointestinal tract within 30 to 60 minutes after ingestion. The stomach absorbs about 20 percent, the remainder is absorbed in the small intestine. About 10 percent of alcohol is eliminated from the body by the kidneys and lungs. The amount of alcohol exhaled through the lungs is used to accurately estimate blood alcohol concentration.
For most people, intoxication occurs after two to three drinks. An average drink is 12 ounces of beer, 5 ounces of wine or 1.5 ounces of 80-proof liquor. Your body metabolism processes about one average drink an hour.
Alcohol is a small, water-soluble molecule that is distributed in the body's water. It is a depressant that inhibits responses of the central nervous system. In small quantities, it can impair coordination and thinking. In large quantities in a short period of time, it can be fatal. Excessive amounts over a long period can cause liver damage.
The extent of alcohol's effect on the central nervous system depends upon how much is in your blood and how much blood you have: a ratio. Two of the main determinants for that are body weight and the amount of water in your body. Women have less body water than men of similar body weight, so a woman will tend to have a higher blood alcohol level than a man of the same weight after drinking the same amount of alcohol. As a person ages, body water usually decreases and body fat increases, so blood alcohol levels rise more easily.
Generally, the lower your body weight, the less blood and water you'll have. So, smaller people will usually have a higher ratio of alcohol in their blood if they drink an amount identical to that which a heavier person drinks.
Men and women
Men generally can drink more alcohol than women of the same size before they show the effect of alcohol. Many studies over the last 10 years, however, have shown that women's bodies tend to get rid of the alcohol about 10 percent faster than men's bodies.
A woman's body also absorbs and metabolizes alcohol differently from a man's, according to the National Institutes of Health.
Women have higher blood alcohol levels than men do after consuming the same amount of alcohol. Women are also more susceptible to alcoholic liver disease, heart muscle damage and brain damage. Women are affected more because of their lower levels of body water and because the stomach enzyme ADH, which metabolizes alcohol, is not as active.
Since people usually have a higher fat-to-muscle ratio as they get older, they become less able to maintain tolerable ratios of alcohol in the blood as younger people of the same weight. (Women and older people who maintain a higher-than-average muscle mass will have a greater ability to maintain lower alcohol levels in the blood.)
Other chemicals in the drink
The water in beer or wine provides a little extra buffer for the alcohol over a plain shot of liquor. So a person might feel the effects of beer or wine a little less. The carbon dioxide in champagne, however, increases the rate of absorption of alcohol causing a more rapid effect.
Speed of drinking
Because the body generally metabolizes about a half-ounce of pure alcohol every hour, that is the top rate at which people generally can drink to keep alcohol levels stable in their system. One beer or one shot of alcohol or one glass of wine is equal to about a half ounce of pure alcohol. The metabolic rate varies for everyone, so you must be careful to check your own mental functioning when you drink to verify your own metabolism.
Food in stomach
If you eat an average meal before drinking, the absorption of the alcohol will be slowed considerably -- as much as 10 percent to 50 percent initially. But this effect is temporary.
The type of food consumed is also is a factor in slowing the absorption of alcohol. The more fat in the meal, the longer it will take the stomach to process the food and the slower the absorption of alcohol.
Drinking history, tolerance
The bodies of chronic users have often reached a higher metabolic rate for alcohol, so their systems can actually purge the alcohol at a much higher rate than casual drinkers' systems. On top of that, the chronic users' organs sometimes develop less sensitivity to alcohol, so the actual effects of the same alcohol-blood level for them would be less than for the casual drinker. But the destructive effects of alcohol on the liver and other parts of the chronic user's body can be devastating over time.
Alcohol reacts negatively with more than 150 medications, according to the National Clearinghouse for Alcohol and Drug Information. Common examples include most barbiturates, antibiotics, blood thinners and anti-convulsants (seizure medications). Some drugs, such as aspirin, may slow the absorption of alcohol from the stomach causing higher blood levels. Check with your doctor before drinking alcohol with any medication.
Physical and emotional health
People who are fatigued or highly stressed out will usually have a noticeably stronger reaction to alcohol, possibly feeling greater depression or some other exaggerated response to normal levels of alcohol.
Because the effects of alcohol are usually subtle at first, you may not recognize that your awareness and responses are compromised, experts say.
Examples of drink equivalence
This average-sized dose of alcohol is equal to one-half ounce of absolute alcohol and is sometimes called a "drink equivalent."
-- 12 ounces of 4% alcohol beer equal 0.48 ounce of absolute alcohol
-- 5 ounces of 10% alcohol wine equal 0.50 ounce of absolute alcohol
-- 1.25 ounces of 40% alcohol vodka (80 proof) equal 0.50 ounce of absolute alcohol
-- 1.25 ounces of 43% alcohol whiskey (86 proof) equal 0.52 ounce of absolute alcohol.
Source: Indiana Prevention Resource Center
National Observances for April
Alcohol Awareness Month
Autism Awareness Month
Child Abuse Prevention Month
National Parkinson's Awareness Month
Week of April 1-7
Medication Safety Week
Week of April 12-18
National Volunteer Week
Week of April 19-25
National Environmental Education Week
Week of April 26-May 2
Air Quality Awareness Week
April 5th: Easter Sunday
April 4th-11th: Passover
Click on the link to left under “Downloads” to download the full April EAP Navigator.