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. Type 2 diabetes can be triggered by heavy drinking as a result of changes in how the body responds to insulin. 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. (For further information please see our factsheet F15, Diabetes and stroke. Drinking alcohol in excess can also trigger atrial fibrillation, a type of irregular heartbeat which also raises the risk of stroke. (For further information please see our factsheet F26, Atrial fibrillation and 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.