But, say doctors, silent attacks can do just as much damage to the heart and increase the risk of future attacks just as much as ones that hurt.
In The Early Show's weeklong series "Early Keeps the Beat" Tuesday, Dr. Roshini Raj of New York University medical center, explained that silent and painful attacks both involve a blood vessel blockage preventing blood from nourishing the heart muscle.
"It's mind-boggling, isn't it?" she remarked. "You're actually having a heart attack, the same mechanism, the same cause, the same consequences, but you just don't feel it, and you never know that you had it."
And, she added, silent heartattacks are "absolutely not" minor.
She says no one is sure how a person could have a heart attack without it hurting. It might just be that the person has a higher threshold for pain than other people, or it might result from nerve damage around the heart that prevents the sensation of pain from being transmitted well.
Basically, Raj says, the same people who are at higher risk of getting heart attacks that hurt are the ones in danger of suffering a silent attack.
Risk factors include diabetes, high blood pressure, smoking, a family history of heart trouble, and high cholesterol.
Silent heart attacks frequently go undetected until after the fact, Raj adds. The common test called the electrocardiogram can pick it up. So can a stress test, and a blood test that picks up on the presence of certain hormones.
So, if you have cardiac risk factors, you should make sure you get a regular physical that includes an EKG. Other ways to detect that a person has suffered a silent heart attack include a stress test, or a blood test that detects certain hormones in the blood.
Raj says silent heart attack can cause symptoms after-the-fact. If you find yourself fatigued more than you did in the past, or a certain amount of exercise is harder to endure than it had been, those could be signs of heart damage from a silent heart attack,and it would be a good idea to get yourself checked out and, if necessary, treated.