A new study has found you are 17 times more likely to have a heart attack if you’ve recently had a respiratory infection.

Researchers from Sydney University say the increased risk is there for up to a month after the infection has subsided and that people should be aware of the potential danger.

“It peaks in the first seven days and gradually reduces but remains elevated for one month,” Professor Geoff Tofler, from the University of Sydney and the Royal North Shore Hospital, told the ABC.

“This is the first study to report an association between respiratory infections such as pneumonia, influenza and bronchitis and increased risk of heart attack in patients confirmed by coronary angiography (a special x-ray to detect heart artery blockages).”

With winter just around the corner, colds and chest infections are on the rise.

The study, published in the Internal Medicine Journal, says the absolute risk of a heart attack after contracting a chest infection is low, but warns people should take all preventative measures available to avoid getting sick.

Read more: Everything you need to know about the flu this winter

It is thought the increased risk is due to the infection activating the blood cells and clotting system, which can lead to a higher risk of blood clots.

Have you had a chest infection recently? Have you had your flu shot this year?