It's official. A glass of wine a day keeps heart risk at bay -- at least for women.

Researchers at Sweden's Karolinska Institute in Stockholm found that women who had already suffered a heart attack or had heart surgery for blocked arteries had higher Heart Rate Variability (HRV) if they drank moderately than if they were teetotal.

HRV measures the intervals between heartbeats, with lower rates being associated with higher risks of heart disease and death.

"We found that women who drank five grams or more of wine a day had increased Heart Rate Variability," Professor Staffan Ahnve stated.

But he warned against binge drinking. What was beneficial was a limited regular intake.

More importantly the results were strongly seen with wine, with little effect from beer or spirits.

The results were published in the British Medical Association's specialist journal Heart.