'Tis the season to be jolly, but...
How much alcohol is too much?
ETHANOL consumption, also known as alcohol use, is widespread in most cultures globally, especially during festive seasons such as Christmas. Polls show that half of all adults in the Western world consume alcohol.
When used in moderate amounts alcohol does not cause injury to the healthy human body. In fact, current research advocates drinking one or two glasses of red wine daily as a protective measure against cardiovascular (heart and blood vessel) diseases. This recommendation however, should be individualised by a physician.
The slogans, "don't drink and drive", "drink responsibly" or "have a designated driver if you drink" are being emphasised by the National Road Safety Council and other stakeholders with good reason. Worldwide an estimated 3.2 per cent of all deaths are due to alcohol use.
In the USA, alcohol consumption is responsible for more than 100,000 deaths annually with 50 per cent being due to drunk driving. In Jamaica the road deaths in 2012 were 9.5 per 100,000. As one of the responses to this problem, the breathalyzer programme was introduced in 1995 to help to deter persons in Jamaica from driving under the influence of alcohol.
Alcohol is absorbed unchanged after intake by the stomach and small intestine and then sent to the tissues and body fluids in the same concentration that it was in the blood. Less than one-tenth is excreted in urine, sweat and breath. The amount that is exhaled is the same as the concentration in the blood and hence the breathalyzer test is used by law enforcement to charge people for driving under the influence (DUI) or driving while intoxicated/impaired (DWI).
This limit varies according to country. In Jamaica, drunk driving is where the corresponding Blood Alcohol Level is 80mg/dl. This limit is reached in the average person with three standard drinks of beer (12 ounces), 15 ounces of wine and 4-5 ounces of 80-proof distilled spirits.
When blood alcohol levels reach 200mg/dl the drinker feels drowsy, at 300mg/dl they will become stuporous with coma and respiratory arrest occurs at higher levels, in other words, the drinker could stop breathing.
Majority of the ethanol is broken down in the liver and the rate of its breakdown affects the blood alcohol level. People who drink lots of alcohol over a period of time (chronic alcoholics) are able to tolerate up to 700mg/dl of alcohol mainly due to increased enzymes in the liver which break it down at a faster rate. Age, sex, race, genetics, body fat, and food in the stomach will also determine the effects of alcohol on the body after intake.
Acute alcohol intake affects the central nervous system (brain and spinal cord) mainly. It is a depressant and affects the subcortical structures of the brain that governs cerebral activity (higher functions). This results in stimulation and disordered cortical, motor and intellectual behaviour. When the alcohol levels are increased, the lower medullary centres are depressed, for example the areas that control respiration, and this may lead to respiratory arrest.
Safe driving requires alertness and the ability to make quick decisions. Alcohol slows the reflexes and decreases the ability to react to changing situations on the road. The eye muscle movements do not coordinate well with the hand and feet actions. Judgement, concentration, coordination, and comprehension are significantly impaired with the excessive use of alcohol.
Therefore, simple driving maneuvers that were once easy to carry out become a task and the driver is now a danger to himself, his passengers and other motorists and pedestrians on the road.
Dr Romayne Edwards is a Consultant Emergency Physician at the University Hospital of the West Indies and an Associate Lecturer at the University of the West Indies.