Alcohol has a biphasic effect on blood pressure and increases heart rate

Review question

We reviewed available evidence about the short‐term effects of different doses of alcoholic drinks compared to non‐alcoholic drinks on blood pressure and heart rate in adults (≥ 18 years) with both normal and raised blood pressure. 

Background

Drinking excessive alcohol is considered one of the most common causes of raised blood pressure. We wanted to quantify the effects of a single dose of alcohol on blood pressure and heart rate within 24 hours of consumption. 

Study characteristics

We included 32 randomised controlled trials involving 767 participants published up to March 2019. Although these trials included adults from 18 to 96 years of age with various health conditions, most study participants were young healthy males. The source of funding was not reported for a majority of the studies. 

Key results

For low doses of alcohol, we found that one glass of alcohol had little to no effect on blood pressure and increased heart rate within six hours of drinking. 

We are moderately certain that medium‐dose alcohol decreased blood pressure and increased heart rate within six hours of consumption. We did not see any significant change in blood pressure or heart rate after that, but the evidence was limited. 

We are also moderately certain that high‐dose alcohol decreased blood pressure within six hours, and the effect lasted up to 12 hours. After that, blood pressure was found to be increased. Heart rate increased significantly after alcohol consumption and remained increased at all times measured. 

Thus alcohol decreases blood pressure initially (up to 12 hours after ingestion) and increases blood pressure after that. Alcohol consistently increases heart rate at all times within 24 hours of consumption. 

Read this review: Effect of alcohol on blood pressure