5 Signs You've Already Had a Heart Attack

 A "silent heart attack" might seem to be a contradiction in terms. Surely, such a serious health event—in which a blockage prevents adequate blood from flowing to the heart, still the #1 cause of death in the U.S.—can't happen without you even noticing, right? 

Not so. In fact, "Nearly half of people who have a heart attack don't realize it at the time," says Harvard Medical School. "These so-called silent heart attacks are only diagnosed after the event, when a recording of the heart's electrical activity (an electrocardiogram, or ECG) or another test reveals evidence of damage to the heart." That's dangerous, because an untreated heart attack can cause irreversible harm to the heart or be fatal.  

In May, a Danish study found that 1 in 4 heart attacks may present with atypical symptoms that can easily be brushed off or confused for other disorders.  

1. Mild Discomfort in Your Chest

Heart attacks don't always announce themselves with the classic symptom of severe pain in the chest. In fact, only half of heart attacks present in this way, says Harvard Medical School. Instead, you might feel only mild discomfort, pressure, tightness, or squeezing in the chest area. 

2. Neck or Jaw Pain

Pain in the arm or jaw can be a subtle sign of a heart condition, particularly in women. In the jaw, the pain may be felt in the lower left area. This pain may come on suddenly, wake you up at night, or begin or worsen with exercise. 

3. Dizziness or Fatigue

A damaged heart has trouble keeping blood flowing to the brain and circulating efficiently throughout the body. This decreased blood flow can cause lightheadedness, dizziness, or fatigue. Women are particularly prone to this symptom. If you have unexplained fatigue or dizziness, it's a good idea to get it checked out.

4. Nausea

Queasiness can't always be chalked up to something you ate or acid reflux—nausea is a commonly overlooked symptom of a heart attack, says Kristin Hughes, MD, a board-certified emergency medicine physician based in Chicago. This is especially true for women, elderly people, and people with diabetes.

5. Shortness of Breath

If you're having frequent shortness of breath without chest discomfort, you should have your heart checked out, says Hughes. In some cases, this can be caused by pulmonary edema, a condition in which the lungs fill with fluid after cardiac tissue has been damaged by a heart attack. People with asthma might think this is a worsening of those symptoms, when in fact it's much more serious.