Sydney, May 16 (IANS): A spell of respiratory infections such as pneumonia, influenza and bronchitis may increase your risk of suffering a heart attack by 17 times, a research has showed.

The findings showed that the increased risk is not necessarily just at the beginning of respiratory symptoms, it peaks in the first seven days and gradually reduces but remains elevated for one month.

"Our findings confirm what has been suggested in prior studies that a respiratory infection can act as a trigger for a heart attack," said Geoffrey Tofler, professor and cardiologist at the University of Sydney.

"Possible reasons for why respiratory infection may trigger a heart attack include an increased tendency towards blood clotting, inflammation and toxins damaging blood vessels, and changes in blood flow," Tofler added.

In addition, people suffering from milder upper respiratory tract infection symptoms such as the common cold, pharyngitis, rhinitis and sinusitis, also had a 13 fold elevated risk of suffering a heart attack.

"Although upper respiratory infections such as common cold, pharyngitis, are less severe, they are far more common than lower respiratory tract symptoms," explained Lorcan Ruane from University of Sydney.

For the study, published in the Internal Medicine Journal, the team investigated 578 patients with heart attack due to a coronary artery blockage, who provided information on recent and usual occurrence of symptoms of respiratory infection.

People should take measures to reduce exposure to infection, including flu and pneumonia vaccines where appropriate, the researchers suggested.

"Our message to people is while the absolute risk that any one episode will trigger a heart attack is low, they need to be aware that a respiratory infection could lead to a coronary event. So consider preventative strategies where possible, and don't ignore symptoms that could indicate a heart attack," Tofler added.