While scientific research has established a link between moderate alcohol consumption and better heart health, a new study suggests that this connection is actually quite complex with potential risks as well as benefits. In fact, new findings show that in the hour following even moderate consumption of alcohol, the risk of heart and stroke doubles.
“Most prior research has focused on the long-term risk of heart attacks and strokes associated with alcohol consumption, but the immediate risks have not been well-documented,” said lead author Elizabeth Mostofsky, ScD, a post-doctoral fellow at Beth Israel Deaconess Medical Center (BIDMC) and an instructor at the Harvard T.H. Chan School of Public Health.
“This new study highlights the fact that alcohol has complex physiological effects that result in both higher and lower cardiovascular risk depending on the amount of alcohol consumed, drinking frequency, and what aspect of heart health is being measured.”
To better understand the risk of heart attack and stroke in the hours and days after drinking alcohol, the researchers looked at data from 23 studies involving 30,000 participants.
“We found that even moderate alcohol consumption — one drink a day for women and up to two drinks a day for men — may raise a person’s risk of a heart attack or stroke approximately two-fold within the hour following consumption compared to other times,” Mostofsky said.
“After 24 hours, though, only heavy alcohol intake conferred a continued heightened risk. In other words, heavy drinking increases risk both in the short-term and the long-term, but drinking smaller amounts has different effects in the subsequent hours than it does in the subsequent days and weeks.”
Just after alcohol consumption, heart rate increases, blood pressure rises, and blood platelets become stickier. This may increase the risk of heart attack and stroke.
But over time, regularly drinking small amounts of alcohol appears to lower cardiovascular risk by increasing levels of high-density lipoprotein cholesterol (HDL), known as the “good” cholesterol, and by reducing the tendency to form blood clots.
“It’s possible that the briefly higher cardiovascular risk in the hours after drinking small amounts of alcohol may be outweighed by the longer-term health benefits of regular moderate drinking,” said Mostofsky.
“However, heavy alcohol use was associated with higher heart attack and stroke risks at all times studied. Six to nine drinks in a day nearly doubled the risk, and 19 to 30 drinks weekly elevated the risk by up to six times more.”
Heavy drinking is defined as consuming 15 or more drinks per week for men and more than eight drinks per week for women, according to the 2015 Dietary Guidelines for Americans published by the U.S. Office of Disease Prevention and Health Promotion.
Moderate drinking is up to one drink per day for women and up to two drinks per day for men. A drink is one 12-ounce beer, four ounces of wine, one and a half ounces of 80-proof spirits, or one ounce of 100-proof spirits.
The findings are published in the journal Circulation.