Drinking wine, but not beer or spirits, keeps women's hearts beating healthily, Swedish research suggests.
Red wine is thought to be good for the heart
Scientists studied the effect of alcohol consumption on 102 women under the age of 75 who had survived a heart attack or surgery for blocked arteries.
They found those who drank a small amount of wine every day for a year had the healthiest heart beat rhythm.
Drinking beer or spirits did not seem to have the same effect, the Karolinska Institute team told the journal Heart.
Much of the research on the potential health benefits of alcohol has been done on men, and it is still not clear exactly why moderate amounts of wine seems to be good for heart health.
The Stockholm research team asked 102 women under the age of 75. to record their alcohol intake over the course of a year.
And after at least a year, a heart tracing (ECG) was taken over 24 hours during routine activities in all the participants, to test heart rate variability (HRV).
HRV measures the changes in time intervals between the beats of the heart.
Decreased variability has been associated with an increased risk of heart disease and death.
This is because a decreased variability indicates that the heart is less able to respond to the need, for instance, to speed up blood flow around the body during exercise.
HRV was highest in women who drank five or more grams of alcohol a day, equivalent to more than half a standard unit, and lowest in those who drank no alcohol at all.
But further analysis showed that the type of alcohol consumed was important.
HRV was highest among women who drank wine, even after taking account of other influential factors, such as age, weight, and smoking habit. Beer and spirits had little impact on HRV.
Researcher Professor Staffan Ahnve told the BBC News website that it was possible drinking wine helped to calm the nervous system, which might have a beneficial effect on heart rhythm.
Also people who drank wine often slept better, which might also make them more relaxed.
Dr Charmaine Griffiths, of the British Heart Foundation, said: "We have known for some time that moderate consumption of alcohol (1-2 units per day) might protect against coronary heart disease.
"This research suggests that the type of drink may be important and adds to the evidence that red wine may have specific benefits over and above other alcoholic drinks.
"In the short term, the good news is that we can all enjoy alcohol in moderation.
"However, drinking too much can have an adverse effect on health. It can damage the heart muscle, increase blood pressure and lead to weight gain."
Dr Griffiths said more research was still needed to discover the exact
beneficial effects of alcohol on heart health, and could not recommend that non-drinkers start drinking alchohol based on the latest findings.
"Our advice remains the same - the best way to reduce the risk of heart disease is to stop smoking if you smoke, increase levels of physical activity and eat a healthy, balanced diet."