How much alcohol does it take to kill a human being?

On May 13, a 27-year-old KTV hostess died after consuming 18 glasses of hard liquor. The amount of alcohol she drank was 9 times more than the recommended amount by the Health Promotion Board.

But exactly how much is too much? While drinking alcohol in moderation isn't harmful, overindulging in one's tipple of choice can lead to both long and short-term health problems.

While the long-term health problems have been well-documented, here's a look at how badly drinking too much booze can immediately affect a person.

Moderate drinking is defined as one drink per day for women and two for men. One drink is defined as a can (330 ml) of regular beer, half a glass (175 ml) of wine or 1 nip (35 ml) of spirit. People overdose on alcohol when their Blood Alcohol Content (BAC) is enough to impair them to the point of risking harm.

BAC is measured by the concentration of alcohol in a person's blood. In Singapore, a BAC of 0.08% - or 80 milligrammes of alcohol in 100 millilitres of blood - means a person is too intoxicated to drive. Those who undergo breathalyser tests are considered intoxicated if more 35 microgrammes of alcohol per 100 millilitres of breath is detected.

This is what the U.S. National Institute of Alcoholism and Alcohol Abuse says is the effect of BAC on a human body:

 

Here's a look at the estimated effect of beer, 3 hours after consumption, on a person's BAC:

 

BEER (4.5% alcohol volume)
  Male (80kg) Female (65kg)
3 cans 0.015% 0.045%
6 cans 0.08% 0.141%
12 cans 0.212%

0.332%

Here's what the effect of wine looks like:

WINE (12.5% alcohol volume)
  Male (80kg) Female (65kg)
3 glasses
0.025% 0.06%
6 glasses
0.101% 0.171%
12 glasses
0.253% 0.392%

 And this is the effect of hard liquor:

LIQUOR (40% alcohol volume)
  Male (80kg) Female (65kg)
3 shots
0.022% 0.055%
6 shots 0.095% 0.162%
12 shots 0.241% 0.375%

 

The most common way BAC spikes is when people drink too much, too fast. This is because the liver has to filter out the alcohol in your bloodstream and can only process a limit amounted of alcohol at a time. The body also absorbs alcohol more quickly than food, which means it hits out bloodstream faster. This is what causes people to overdose.

There are different degrees of overdoses, ranging from slurred speech and lack of balance - a condition many people exhibit when drunk - to more serious effects, including a coma or death. There are several factors that influence a person's alcohol tolerance, from age to drinking experience and even things like gender and ethnicity.

Alcohol poisoning can happen when a person's BAC is so high that the parts of the brain that control life-support functions like breathing and heart rate starts to malfunction.

People with alcohol poisoning show signs like confusion, vomiting, seizures, breathing difficulties and low body temperatures, among others.

The really worrying part is that a person's BAC can rise even after they are unconscious, because the stomach and intestines continue to release alcohol into your bloodstream.

Never assume an unconscious person will be fine once they wake up. People who've passed out have choked to death on their own vomit due to the fact that alcohol overconsumption inhibits the body's gag reflex. The right thing to do when somebody has alcohol poisoning is to get medical help. Cold showers, coffee or trying to walk it off will not help. In fact, it may just make things worse.