How to recognize the warning signs of a silent heart attack — and why it can still be dangerous

• Silent heart attacks are just as dangerous and common as traditional heart attacks.
• Silent heart attacks are milder than traditional heart attacks and may not come with any symptoms.
• People who have a silent heart attack may not know it and therefore don't seek necessary treatment.

Heart attacks often have a classic roster of symptoms: chest pain, shortness of breath, and the sensation of something heavy on the chest. But not always.

Silent heart attacks, more formally known as a silent myocardial infarction (SMI), are "silent" because symptoms are so mild that people often do not realize they occurred.

But that doesn't mean you can ignore a silent heart attack — medical experts say it's just as dangerous as a traditional one. Here's how to tell if you're having a silent heart attack and what to do about it.

What is a silent heart attack?

A 2015 study published in the journal Circulation of nearly 10,000 participants compared silent heart attacks and traditional ones, and found that silent heart attacks accounted for nearly half of all heart attacks.

Nicole Weinberg, MD, a cardiologist at Providence Saint John's Health Center, says there can be situations where people have no symptoms with a silent heart attack. But often, there are a few mild symptoms that can be difficult to recognize.

These include fatigue, heartburn, discomfort in the chest, back, or jaw, and shortness of breath, according to the American Academy of Family Physicians (AAFP). A traditional heart attack can have similar symptoms, but also often includes a sensation of pressure or pain in the chest, arms, neck, back, and/or jaw.

Furthermore, the symptoms of a silent heart attack can easily be mistaken for something else, such as indigestion, a challenging workout, or even a toothache. And even though the symptoms may not feel severe, Weinberg says a silent heart attack is just as serious as any other heart attack.

Why silent heart attacks are dangerous

Heart attacks — both silent or traditional — occur when insufficient blood flows to the heart. And, a silent heart attack is just as dangerous as a traditional one. It increases your likelihood of another heart attack, as well as the potential for heart failure.

"It's critical to open up a blocked heart artery as soon as it's blocked so we're not in a situation where there's decreased blood flow and ultimately scar tissue that would impair somebody's ability to have normal heart function," Weinberg says.

While the Circulation study found that silent heart attacks were more common in men than women, it also found that women were more likely to die as a result of one. This may be due to women — and their doctors — not necessarily taking symptoms seriously enough, according to the American Heart Association.

Also, researchers have found that silent heart attacks are more common in older adults with diabetes. For example, in a study published in 2012 in the Journal of the American Medical Association, 14% of the 337 participants with diabetes experienced a silent heart attack compared to 9% of the same population that had a traditional heart attack.

And with a traditional heart attack, doctors can recommend treatments that include surgery, medications, and lifestyle adjustments. That's why silent heart attacks are so worrisome: If you don't know you had a heart attack, you won't take advantage of treatment and prevention tactics.

Moreover, you may only realize you had a heart attack after the fact when you start to experience symptoms of heart failure because the silent heart attack has damaged the heart muscles.

How to recognize the signs of a silent heart attack

If you think you might be experiencing symptoms of a heart attack, you should go to the emergency room immediately. But in most cases of silent heart attacks, the symptoms are so mild or nonexistent that a person wouldn't necessarily think to go to the ER.

Often, the diagnosis occurs in a routine physical or during a doctor's visit prompted by lingering symptoms such as fatigue, shortness of breath, and indigestion.

The risk factors are the same for a traditional and silent heart attack: A family history of heart attacks, older age, lifestyle choices such as smoking or insufficient exercise, obesity, and conditions such as high blood pressure, high cholesterol, and diabetes.

Insider's takeaway

A silent heart attack is just as dangerous as a regular heart attack. If your doctor suspects you had a silent heart attack, the likely next step will be for you to get an electrocardiogram (EKG), which will show your heart's electrical activity and reveal damage to the heart caused by a heart attack, says the Society for Cardiovascular Angiography and Interventions.