How Does Alcohol Affect Blood Pressure?

Alcohol is one of the most common avoidable causes of high blood pressure. The more you drink, the higher your blood pressure tends to be, and cutting back lowers it within weeks. For people with hypertension, drinking less is one of the simplest and most effective lifestyle changes.

Short-term effects: down, then up

After drinking, blood pressure often falls slightly for a few hours because alcohol widens blood vessels. Studies show that after larger amounts it then rises again and can stay higher for the rest of the day and the following morning, together with a faster heart rate. This is one reason why readings after an evening of drinking can be confusing, and why you should not measure blood pressure shortly after drinking.

Long-term effects

Regular drinking raises blood pressure in a dose-dependent way: the more alcohol, the higher the readings and the greater the risk of developing hypertension. Recent analyses suggest that even about one drink a day is linked to a small rise in blood pressure, so there is no amount that is "good" for blood pressure.

The mechanisms include:

• activation of the sympathetic ("fight or flight") nervous system, which narrows blood vessels and speeds up the heart
• stimulation of hormones such as renin, angiotensin and cortisol that retain salt and water
• effects on the lining of blood vessels and on the body's blood pressure sensors (baroreceptors)
• extra calories that contribute to weight gain

Heavy drinking can also make high blood pressure hard to treat, and it weakens the heart muscle, raises the risk of atrial fibrillation and increases the risk of stroke.

How much does cutting back help?

In people with high blood pressure, reducing alcohol lowers systolic pressure by about 4 mmHg on average. The effect is larger in heavy drinkers: in studies of people who had more than two drinks a day and cut their intake by about half, systolic pressure fell by about 5 to 6 mmHg. The effect starts within a few weeks. For people who drink little, the change is smaller.

What is "one drink"?

The size of a standard drink differs between countries. In the US, one drink contains about 14 g of pure alcohol; in the UK, a unit is 8 g; in many other countries a standard drink is about 10 g.

Restaurant and home servings are often larger than these, especially for wine.

Recommended limits

• US guideline (ACC/AHA): people with high blood pressure who drink should limit themselves to no more than two drinks a day for men and one for women.
• European guideline (ESH 2023): less than 14 units a week for men and less than 8 units a week for women, and avoid binge drinking.

These are upper limits, not targets. For blood pressure, less is better, and not drinking at all is best.

Practical tips

• Plan several alcohol-free days each week.
• Avoid binge drinking: several drinks in one evening raise blood pressure more than the same amount spread out.
• Choose smaller glasses, lower-strength or alcohol-free beer and wine, and alternate alcoholic drinks with water.
• Be aware that alcohol can interact with blood pressure medicines and cause dizziness.
• If you drink heavily every day, do not stop suddenly without medical advice. Withdrawal can be dangerous and also raises blood pressure temporarily; your doctor can help you cut back safely.

See also: 5 Quick and Easy Ways to Lower Your Blood Pressure, risk factors for high blood pressure and hypertension stage 1 (grade 1).