Chronic anxiety may be bad for your heart. A new study shows that constant worrying can significantly increase the risk of a heart attack, at least in men.

Researchers studied 735 men who completed psychological testing in 1986 and had good cardiovascular health. The men in the study were then tracked an average of 12 years, during which time they filled out questionnaires about smoking, alcohol consumption and their diet, and had medical exams every three years.

Those men who were in the highest percentile for all anxiety scales were found to be at a 30 to 40 per cent higher risk of heart attack. The scales included:

• Excessive doubts, obsessive thoughts and irrational compulsions.
• Social introversion, or anxiety, insecurity, and discomfort in interpersonal and social situations.
• Phobias, or excessive anxieties or fears about animals, situations or objects.
• Manifest anxiety, measured the tendency to experience tension and physical arousal in stressful situations.

"These psychological factors are important in predicting the risk of heart disease, but anxiety is unique," said Biing-Jiun Shen, an assistant professor of psychology at the University of Southern California in Los Angeles, in a release. "Older men with sustained and pervasive anxiety appear to be at increased risk for a heart attack even after their levels of depression, anger, hostility and Type A behaviour are considered."

Doctors say the research is important because patients are usually treated for the physical factors leading to heart trouble, but not the psychological ones. They say physicians need to be aggressive about "really getting into their patients' heads."

The researchers note that everybody gets anxious every now and then about things like having to give a big speech. Where there could be a problem is being a chronic worrier, somebody who's fearful and socially withdrawn.

"The good thing about anxiety is that it's very treatable," said Shen. "If someone is highly anxious — if they're suffering from panic attacks or social phobia or constant worry — we recommend therapy."

He says anxious personality traits are considered "markers" for heart disease and not outright "risk factors" like cholesterol or blood pressure.

The study appears in the Jan. 15 issue of the Journal of the American College of Cardiology.

With files from the Associated Press