Alcohol Effects: Alcohol and Stroke

Alcohol Effects: Alcohol and Stroke - This factsheet explains how regularly drinking more alcohol than the recommended levels can increase your risk of stroke. It includes tips on keeping track of how much you drink and reducing your intake, and lists sources of information and support.    

What is alcohol and how is it measured?

Alcoholic drinks are made when grains, fruits or vegetables are put through a process called fermentation. This produces cider, beer and wine. After fermentation, a further process called distillation is used to produce spirits such as gin, whisky and vodka. 

Alcohol strength is measured in percentage of alcohol by volume (per cent ABV). The higher the ABV, the stronger the drink is. Beers and ciders typically contain between 3.5% per cent and 9 per cent ABV while wine is usually between 12 per cent and 14 per cent ABV. Spirits typically contain 40 per cent ABV. 

Alcohol consumption is measured in units. One unit is:

• a small glass of wine
• a single pub measure of spirits such as gin, vodka or whiskey, or
• half a pint of ordinary strength (3-4 per cent) beer, lager or cider.

The Department of Health recommends that women should not regularly drink more than 2-3 units a day, and men should not regularly drink more than 3-4 units a day. 

Excessive drinking or ‘binge’ drinking is when more than 8 units are consumed by men or more than 6 units by women in any one hour.

Because of alcohol’s toxic effects on the whole body, doctors are now recommending that regular drinkers should have three alcohol-free days every week.

What are the effects of alcohol?

Alcohol is absorbed from the stomach and small intestine directly into the bloodstream. It primarily acts as a depressant, which means that it slows down signals in the nerves and brain. Initially alcohol stimulates feelings of relaxation and happiness and activates the brain areas involved in thinking and pleasure-seeking. But when consumed to excess, alcohol can cause:

• delayed reactions and impaired judgement
• slurred speech
• poor balance and falls
• blurred vision and headaches  
• exaggerated or extreme emotions 
• memory loss and confusion
• long term ill-health

As well as increasing the risk of stroke, regular heavy drinking can lead to cancers, liver disease, osteoporosis and alcohol-related brain damage. As we get older, we lose muscle, gain fat, and break down alcohol more slowly, and these factors make us more sensitive to the effects of alcohol. Women’s bodies process alcohol less effectively than men’s because they have more fat and less fluid. Alcohol can therefore be more damaging to women’s health.

Osteoporosis (a condition where bone density is reduced and the risk of fractures increases) becomes more common in later years, particularly for women, and is more likely to develop in heavy drinkers.  

The recommended limits are based on evidence relating to younger age groups, so as we get older we should cut down on alcohol to protect our health.

How does drinking alcohol increase the risk of stroke?

Alcohol contributes to diseases that affect the circulation of the blood, such as high blood pressure and diabetes, and these in turn raise our risk of stroke. Excessive drinking, where the recommended limits are regularly exceeded, and ‘binge’ drinking, can both raise blood pressure, which is the main risk factor for stroke.

High blood pressure develops when the pressure of the blood passing through the blood vessels is consistently high – above 140/90 mmHg. Ideally, blood pressure should be no higher than 120/80 mmHg. It is now thought that variable blood pressure which reaches very high levels from time to time also raises our risk of stroke

Type 2 diabetes can be triggered by heavy drinking as a result of changes in how the body responds to insulin. Because alcoholic drinks are so high in calories, drinking can increase your chance of becoming overweight, which also raises your risk of developing type 2 diabetes. Heavy drinking also causes pancreatitis (inflammation of the pancreas) which can reduce insulin production, and one in three people with this condition will develop diabetes.

Heavy drinking is dangerous for your heart in many ways. It can raise your levels of both cholesterol and triglyceride (a type of fat in the blood), increasing your risk of getting heart disease or a stroke. Drinking alcohol in excess can also trigger atrial fibrillation, a type of irregular heartbeat which also raises the risk of stroke.

Even in moderate amounts, alcohol may lead to a rise in the blood level of a substance called homocysteine.This can increase the risk of your blood clotting and is also linked to atherosclerosis (hardening and furring of the internal walls of the arteries). This can result in a blockage forming, which could lead to a stroke. 

Another reference