Constantly worrying about having a heart attack may make it more likely you’ll have one, Norwegian researchers report.

In fact, people dubbed the “worried well” were twice as likely to develop chest pain or have a heart attack compared to those who weren’t anxious about their health, the new study found.

“People with high levels of health anxiety have about a 70 percent increased risk of heart disease, after taking [into] account other known risk factors,” said lead researcher Dr. Line Iden Berge. She’s from the division of psychiatry at the University of Bergen in Norway.

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Even relatively low levels of health anxiety can increase the risk, compared to people without symptoms of health anxiety, she said.

This study, however, wasn’t designed to prove that fretting over your health caused heart problems, only that these things seemed to be associated.

Because these findings can’t be explained by risks for heart disease -- such as smoking, lack of physical activity, drinking alcohol or a family history of heart disease -- the increased risk may be “caused by physiological effects of the anxiety itself,” Berge said.

“This new evidence of negative consequences over time emphasizes proper diagnosis and treatment of health anxiety,” she said.

For the study, Berge and her colleagues collected data on more than 7,000 people who took part in the Norwegian Hordaland Health Study. The participants, all of whom were born between 1953 and 1957, completed two questionnaires about their health, lifestyle and education. In addition, between 1997 and 1999, they had a physical checkup that included blood tests, weight, height and blood pressure.

Levels of anxiety about health were assessed. Berge’s team found that just over 700 people had scores that identified them as anxious about their health.

All of the people in the study were followed until the end of 2009. Those treated for heart disease or who died from it within a year after the start of the study were excluded, because they might already have been ill, the researchers said.

In all, 3 percent of the participants (234 people) had a heart attack or acute chest pain (angina) during follow-up. The average time to the first incident was just over seven years, the findings showed.

The proportion of those who developed heart disease was twice as high among the worried well as it was among those not anxious about their health -- 6 percent versus 3 percent, respectively.

The report was published online Nov. 3 in the journal BMJ Open.

Dr. Stacey Rosen is vice president for women’s health at Northwell Health’s Katz Institute for Women’s Health in New Hyde Park, N.Y. She said the “relationship between behavioral health issues and cardiac health is a critical part of everything we do for cardiac patients.”

In the past, the worried well were not taken seriously, she said. “But it’s clear that having health anxiety is not good for you,” added Rosen, who not involved with the new study.

The first step for people with health anxiety is to find a doctor that “you really have faith in,” Rosen said. “Having a caregiver you trust and who partners with you to customize the approach to your health is number one,” she said.

Also, learning about the health conditions you are worried about is important. “But I always recommend to patients that their research should come from credible sites, such as the U.S. National Institutes of Health, not random information online,” she said.

Patients with these anxieties should be referred to mental health professionals for treatment, Rosen added.

Dr. Matthew Lorber is acting director of child and adolescent psychiatry at Lenox Hill Hospital in New York City. He said, “When most doctors encounter someone who they think is a hypochondriac, they kind of reassure them that it’s nothing, you’ll be fine, it’s just in your head.” But “this is a problematic approach, because if you don’t actually treat the anxiety, then they are going to be at risk for serious heart disease,” Lorber said.

“We now call this problem ‘illness anxiety disorder,’ “ he said.

Lorber recommends seeing a mental health expert and perhaps taking anti-anxiety medication. “Therapy really helps, and anti-anxiety medication may make the therapy more effective,” he said.