When assessing intoxication what factors should you take into account that may affect individual responses to alcohol?

There are many important individual factors and circumstances that affect blood alcohol concentration (BAC) levels.

The faster an individual drinks, the quicker their peak BAC will raise and the more quickly they will become intoxicated. The liver metabolizes alcohol at a rate of approximately one standard drink per hour; 12 oz. beer, 5 oz. wine, .5-ounces or a "shot" of 80-proof distilled spirits or liquor (e.g., gin, rum, vodka, or whiskey). If more than one drink per hour is consumed, the liver is unable to keep pace and more alcohol will circulate in the blood stream until the liver can catch up. The more alcohol in the blood, the higher the intoxication level.

On average men have 76 c.c. of blood /kg body weight and in women it is 66 c.c. of blood /kg body weight. Not only do men have more blood in which to dilute alcohol by virtue of their greater size but even men of the same weight as women have slightly more blood in which to dilute alcohol. This is because muscle tissue contains more water than fat tissue, so men -- who have more muscle and less fat on the average than women -- can have about 10 percent more water in their bodies.

It is commonly thought that higher altitudes will cause intoxication more quickly than at sea level. Studies for the Federal Aviation Administration do not confirm the common belief. Additionally, for those living at higher altitudes the body compensates for the thinner air by producing more blood in which to carry oxygen. More blood by weight provides more dilution of alcohol.

About 20 percent of alcohol is absorbed into the bloodstream directly through the walls of the stomach and 80 percent is absorbed into the bloodstream through the small intestine. When there is food in the stomach, alcohol is absorbed more slowly into the bloodstream. Food in the stomach slows the absorption of alcohol by preventing it from going directly to the small intestine which is where the majority of alcohol enters the blood stream. The effects of the alcohol will still occur but at a slower rate.It is a myth that food absorbs the alcohol. It does not. Drinking on a full stomach slows the absorption of alcohol because the stomach's pyloric valve, which connects the stomach and small intestine, closes to allow food to digest. The closed pyloric valve keeps alcohol in the stomach longer before it enters your small intestines.It follows that fatty foods are more effective in slowing alcohol absorption than are other foods because they are more difficult to digest. Carbohydrates are passed through the stomach more quickly causing both the food and alcohol to enter the small intestines more quickly than with high fat content foods.

The pylorus valve may also go into spasm in the presence of concentrated alcohol, trapping the alcohol in the stomach instead of allowing it through to the small intestine. The drinker who downs several straight shots in an effort to get a quick high may actually experience a delayed effect.

Generally, the higher the alcohol concentration of a drink the faster the alcohol will be absorbed into the blood stream. One standard drink of hard liquor does have the same alcohol content as a regular beer. Since hard liquor is frequently less diluted (as in a shot) the effects will be noticed more rapidly.

The definition of a standard drink varies widely by country. In the USA a standard drink is equivalent to:One 12 fl oz. (355 mL) bottle of beer or wine coolerOne 5 fl oz. (148 mL) glass of wine

One mixed drink containing 1.5 fl. oz. (44 mL) of 80-proof hard liquor, such as gin, whiskey, or rum

"Proof" is a measure of how much alcohol is in a given type of alcoholic beverage. In the United States, where the measure is commonly used, proof represents twice the percentage of alcohol by volume. 100 proof means 50% alcohol. 80 proof means 40% alcohol.

The concept of a standard drink, that is 12 oz. beer, 5 oz. wine, .5-ounces or a "shot" of 80-proof distilled spirits or liquor (e.g., gin, rum, vodka, or whiskey) is often not a good guideline for judging your own BAC.

No two bartenders pour the same amount of alcohol and party hosts frequently pour more "Doubles" and drinks made with more than one type of liquor typically contain much more alcohol than the Standard Drink.

Water and fruit juices mixed with alcohol slow the absorption process, while carbonated beverages will speed it up. Carbonated drinks speed alcohol through the stomach and intestine into the bloodstream, creating a more rapid rise in BAC.

Medications can amplify the effects of alcohol on your body. Aspirin, tranquilizers, anti-depressants, and cough medicines to name only a few can effect when mixed with alcohol.

Long term drinkers develop tolerance to alcohol. One reason is that the liver becomes more efficient at metabolizing alcohol. In people with high tolerance to alcohol it takes more alcohol to produce the outward signs of intoxication. BAC is not affected by alcohol tolerance. Someone with higher alcohol tolerance is not safer to drive according the law.

Alcohol has a more pronounced effect on those who may be fatigued or under stress. Since alcohol is a depressant, someone who is depressed will likely become more depressed when drinking.

How alcohol affects you can depend on a range of factors, including your:

• sex
• mental and physical health
• medical conditions
• use of other drugs and medications.

Alcohol can affect you more quickly if you:

• drink on an empty stomach
• have a lower tolerance to alcohol
• have a lower percentage of muscle on your body
• are a young person
• weigh less
• don’t usually drink alcohol.

What happens in your body

As you drink alcohol, it:

• passes into your blood through the walls of the stomach and small intestine
• travels to all parts of the body including the brain
• slows down your brain and affects almost all parts your body
• affects the way you think, feel and behave.

Alcohol only takes a few minutes to reach the brain in an average, healthy person.

Your liver removes most of the alcohol in your body by breaking it down.

Blood alcohol levels

As you drink, the level of alcohol in your blood rises.

The level of alcohol in your blood is called blood alcohol concentration (BAC). A BAC of 0.01 means there is 0.01g of alcohol in 100ml of your blood.

In an average, healthy person, one standard drink:

• increases BAC by about 0.02
• takes about one hour to break down.

But remember, this can be different for everyone.

BAC is what police test for in roadside alcohol breath tests. If you're a fully licensed driver, you're breaking the law in Australia if you drive with a equal to or more than 0.05.

How long alcohol stays in your blood

Drinking more than one standard drink per hour will increase your BAC. The faster you drink, the higher your BAC.

When you stop drinking, your BAC will keep rising as the alcohol in your stomach goes into your blood.

The only way to lower your BAC is time. The more drinks you have, the more time you need.

You cannot remove alcohol from your blood by vomiting, having a cold shower or drinking coffee.

Short-term effects

Drinking alcohol can affect your body straight away. A healthy person is likely to experience the following:

• BAC of up to 0.05:
  • feeling of wellbeing
  • talkative, relaxed and more confident
• BAC of 0.05 to 0.08:
  • impaired judgement and movement
  • reduced inhibitions
• BAC of 0.08 to 0.15:
  • slurred speech
  • impaired balance, coordination, vision and reflexes
  • unstable emotions
  • nausea and vomiting
• BAC of 0.15 to 0.30:
  • unable to walk without help
  • sleepy
  • difficulty breathing
  • memory loss
  • loss of bladder control
  • possible loss of consciousness
• BAC of over 0.30:

In the short term, drinking too much alcohol can also lead to:

• accidental injury (to yourself or others)
• being in a road accident
• deliberately harming yourself or others
• risky sexual behaviour
• family, domestic and sexual violence
• alcohol poisoning
• hangovers.

Binge drinking (drinking a lot of alcohol in one session or a short period) can be even more harmful and risky.

Long-term effects

For both men and women, the risk of dying from alcohol-related disease and injury remains below 1 in 100 if no more than 10 standard drinks are consumed each week and no more than 4 standard drinks are consumed on any one day. The less you drink, the lower your risk of harm from alcohol.

Long-term effects of alcohol consumption above Guideline recommendations include:

If you’re pregnant, or planning a pregnancy, you should not drink alcohol. If you are breastfeeding, not drinking alcohol is safest for your baby. Drinking any amount of alcohol can harm your fetus (unborn baby) or baby.

Social and financial problems

Alcohol can reduce your inhibitions and lead you to behave in a way you normally wouldn’t. You may commit a crime, behave in an antisocial way or do something embarrassing.

Your behaviour could affect your friendships, your work and your family.

If you drink a lot or become dependent on alcohol, you could end up spending a lot of money on your drinking.

Taking alcohol with other drugs

Drinking alcohol at the same time as taking other drugs, including medicine, can be very risky. This is because alcohol can:

• increase the side effects of other drugs
• reduce the effect of medicine such as antibiotics or diabetes medicine
• hide the effect of a drug or medicine.

Reducing the effects

To reduce the effects of your drinking: