Two recently presented studies have suggested that the intake of over ten alcoholic drinks in a week or four cups of strong coffee everyday could increase a person's risk of developing an irregular heartbeat.
According to reports on the studies, alcohol and caffeine intake can increase the chances of developing an abnormal heart rhythm, known as atrial fibrillation, which greatly increases the risk of having a stroke, heart attack or other cardiac problems.
In the first study, involving 8,830 men and women in Britain, Scandinavia and the US, the researchers found that those who drank the equivalent of ten standard drinks - about 15 units a week - had an 80 per cent increased risk of being diagnosed with the condition within five years.
The Department of Health has suggested that men should drink no more than 21 units of alcohol a week, and women no more than 14.
Inger Ariansen, who led the study at Oslo University Hospital, advised that ten standard drinks could be regarded as a threshold for increased risk of atrial fibrillation.
The second study, carried out by researchers at the University of Modena, found that drinking more than the equivalent of four espresso shots a day could increase the risk of arrhythmias in people without known heart disease.
And the condition could develop in such individuals even if they otherwise had a healthy diet.
Peter Weissberg, medical director of the British Heart Foundation, has said that the recommended limits for drinking alcohol a week were formulated to avoid the risk of liver disease and other drink-related health problems.
"But there is no doubt that some patients are more susceptible to the effects of alcohol on the heart and it may be that a subset of people who metabolise alcohol differently are at increased risk of atrial fibrillation," Times Online quoted Weissberg as saying.
He added that he was not aware of any direct evidence that drinking caffeine increased the risk of atrial fibrillation, "but it wouldn't be surprising if you found that".
A presentation on the findings was made at the European Society of Cardiology congress in Barcelona.