Could having pneumonia trigger a heart attack?

You likely already know many of the underlying risk factors that can lead to a heart attack, well, by heart: high blood pressure, high "bad" or LDL cholesterol, family history of heart attack, smoking, lack of exercise, poor diet, diabetes, stress, obesity – the list is not short. But being in overall good health can go a long way toward reducing that risk.

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Not only that, but taking care of yourself may also help reduce a trigger of heart attacks that cardiologists are aware of, even if you're not: respiratory infections.

Recent research found that the risk of a heart attack was 17 times higher in the seven days following a respiratory infection, such as pneumonia or bronchitis. Though heart attack risk dropped after that, it still remained elevated for a month. Those with milder, upper respiratory infections, like the common cold, saw their heart attack risk increase 13.5-fold.

The study, published in Internal Medicine Journal in May, added to the suggested link between respiratory infections and heart attacks. "While the absolute risk that any one episode will trigger a heart attack is low, people need to be aware that a respiratory infection could lead to a coronary event," senior author Dr. Geoffrey Tofler wrote in an email. Tofler's a cardiologist at Sydney University, Royal North Shore Hospital and Heart Research Australia, which supports researchers doing study in the prevention, diagnosis and treatment of heart disease.

[See: 6 Signs You're Having a Heart Attack.]

The extent to which a respiratory illness might raise one's risk of having a heart attack varies by the study suggesting the link. The latest research used coronary angiography, special X-ray imaging to detect heart artery blockages, to confirm heart attacks in 578 patients studied. The researchers noted, though, that the respiratory symptoms were self-reported by patients – so it's possible not all who described having respiratory illness in fact did.

However, doctors say the link between a respiratory infection as a trigger that ticks up the risk for a heart attack has been established – even if it's something most patients don't know about. "While this concept may not be novel to clinicians, it may not be on the public consciousness," says Dr. Dave Dudzinski, cardiologist at Massachusetts General Hospital in Boston.

Of course, underlying cardiovascular risk factors still set the stage. "It's not that pneumonia will take somebody who's completely healthy with no plaque in their arteries and all the sudden make a bunch of plaque show up and give them a heart attack," says Dr. Mike Miedema, a preventive cardiologist with the Minneapolis Heart Institute at Abbott Northwestern Hospital in Minneapolis.

Rather, for a person who already has a buildup of plaque – the accumulation of various substances including calcium, fat and cholesterol – the respiratory illness sharpens the danger. "There's something about the respiratory infection that makes those plaques less stable," Miedema says. When plaque breaks off it can cause sudden clotting that can lead to a heart attack.

Respiratory infections are known to increase platelet (red blood cell) activity that's been associated with heart attack among patients who had pneumonia as well. And infections may also contribute to inflammation in the body, which may play a role in raising heart attack risk.

[See: How to Avoid a Second Heart Attack.]

Confusingly, the symptoms of a respiratory illness and heart problems can sometimes be similar. Got a cold? Don't ignore chest pain, though the likelihood a heart attack would be triggered by a cold is quite low. "Patients who develop a respiratory infection should not dismiss chest pain symptoms as necessarily respiratory and not cardiac in origin," the researchers said in Internal Medicine Journal. Better to get checked out if you're not sure, experts say.

While you're at it, be prompt in treating respiratory illnesses – particularly if you have underlying cardiovascular risk factors. The higher rate of these illnesses as temperatures dip may contribute to the peak of heart attacks in winter, according to previous research. Take preventive medications, such as statins to reduce cholesterol levels and drugs to lower blood pressure, if recommended by your doctor.

Anything that significantly stresses or taxes the body could have an impact on the heart. "It's one of the reasons that we do recommend a flu shot," Miedema says. "We know influenza can have a pretty significant impact on the body, but also we do see cardiovascular complications [for] people who do have severe viral infections." The American Heart Association and the American College of Cardiology recommend an annual flu vaccine in injection form for cardiovascular disease patients "with coronary and other atherosclerotic vascular disease," according to the AHA website.

Research cited in the paper found having a flu vaccine played a protective role in lowering the risk of a heart attack.

For some, a pneumonia vaccine may be appropriate, as well. Historically, these have been recommended for anybody over age 65, and anyone between 18 and 64 who had certain risk factors like being immunocompromised or having severe dysfunction of the liver, kidney, heart, lung or another organ, Dudzinski says. Talk to your doctor to determine if a vaccine is appropriate.

[See: 17 Ways Heart Health Varies in Women and Men.]

"Once a person is exposed to respiratory infection, secondary prevention methods may include prompt treatment of the infection as well as possibly taking aspirin to reduce the transient increase in [cardiovascular disease] risk," the researchers wrote. They reported that the relative risk of heart attack after respiratory infection tended to be lower in patients taking preventive medications – aspirin, statins, beta blockers and ACE inhibitors.

But whether sick or not right now, taking preventive medications as recommended, and making lifestyle changes to be heart healthier, could lower your risk of heart attack – no matter what the next future cold and flu season has in store.

Copyright 2017 U.S. News & World Report