A glass of wine may be good for the heart, but coupled with second-hand smoke — and you may be hurting your health, according to a new study.

Researchers at the University of Alabama at Birmingham tested the effects of drinking alcohol while inhaling second-hand smoke. They found the combination increases the damage cigarette smoke has on the heart.

The researchers reported that mice exposed to smoky air in a laboratory enclosure and fed a liquid diet containing ethanol (the intoxicating ingredient in alcohol) had a 4.7-fold increase in artery lesions, compared to mice breathing normal air and eating a normal diet.

Artery lesions are a common problem in heavy smokers and a sign of advancing cardiovascular disease, according to the study, which is published in the journal "Free Radical Biology & Medicine."

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The researchers reported mice solely exposed to the smoky air had a 2.3-fold increase in artery lesions when compared to mice who breathed filtered air. Mice solely fed a liquid diet containing ethanol had a 3.5-fold increase in artery lesions when compared to mice fed a normal diet.

“Because moderate alcohol consumption is commonly thought to be cardioprotective, these findings are important for smokers and non-smokers alike in terms of what you should and should not do to protect their health,” said Shannon Bailey, an associate professor in the UAB Department of Environmental Health Sciences and a co-investigator on the study, in a news release.

The experiments were performed over a five-week period, according to the report. Blood-alcohol concentrations reached the equivalent of a 150-pound adult consuming two drinks per hour. Cigarette smoke exposure was similar to being in an automobile with a chain smoker with the windows closed.