Moderate Drinking Not Linked to Irregular Heartbeat, Study Says

However, people who consume more than three drinks per day have a higher incidence of atrial fibrillation -- a risk factor for strokes.

Jacob Gaffney
Posted: March 31, 2004

People who drink one or two glasses of wine a day may find their hearts are not all aflutter over the latest research on alcohol and health.

A new study from researchers at Boston University found that light and moderate drinking appears to have little effect on the rhythm of one's heartbeat. But people who drink more than three servings of alcohol per day have an increased risk of atrial fibrillation -- a form of irregular heartbeat -- compared with nondrinkers.

Atrial fibrillation is a known risk factor for strokes. Because the heart beats with arrhythmic timing, blood can pool and clot, and those clots may get dislodged and travel to different areas of the body. If the clot makes it to the brain, it may cause a stroke. According to the study, published in the March 15 issue of the American Journal of Cardiology, atrial fibrillation affects more than 2 million adults in the United States.

In order to gauge the effect of alcohol consumption on atrial fibrillation, a team led by Dr. Luc Djoussé examined data from 1,055 volunteers who participated in the larger Framingham Heart Study. This epidemiological study, which has been going on since 1948, examines the health of thousands of residents of a Massachusetts town and of their offspring.

Study participants received physical exams twice a year until death and filled out questionnaires on their lifestyles, including information on their drinking habits. The volunteers reported whether they were nondrinkers or consumed an average of one drink or less per day, more than one to two drinks per day, more than two to three drinks per day or more than three drinks per day. The researchers defined an average drink as containing 12 grams of alcohol -- or 1.5 to 2 ounces of liquor, 8 to 12 ounces of beer or 4 to 5 ounces of wine.

Framingham study subjects were tested for atrial fibrillation through electrocardiograms, which measure if the heart is beating routinely or if it has a slight "flutter." For their recent study, Djoussé's team examined data from people in their late 30s to mid-50s.

After comparing the electrocardiogram information to drinking habits, the scientists found that people who had up to three drinks per day tended to have heartbeats as regular as those of nondrinkers. Any differences in heartbeat among those categories of consumption were deemed minimal by the team. The results did not change significantly after adjusting for exercise habits.

The only category that showed a higher risk of developing atrial fibrillation were people who consumed three or more drinks per day. They were 34 percent more likely than nondrinkers and other drinkers to have atrial fibrillation, according to the study.

The study authors believe that having more than three drinks in the evening and none during the day may create alternating states of withdrawal and then fulfillment, and that this condition may place added stress on the heart.

However, alcohol consumption was self-reported, the researchers noted, so the results are only as accurate as the people who filled out the questionnaires.

For a comprehensive look at the potential health benefits of drinking wine, check out senior editor Per-Henrik Mansson's feature Eat Well, Drink Wisely, Live Longer: The Science Behind A Healthy Life With Wine

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