(CNN) -- When Eugenie Smith's hands started tingling, she figured her biking gloves needed more padding. When she felt out of breath after a short walk on a treadmill, she assumed it was pneumonia. When her chest hurt, Smith chalked it up to indigestion.
She was wrong, wrong, wrong.
Smith was actually having a heart attack, and needed three stents. She was 46 at the time, and in otherwise perfect health.
While it may sound odd to miss the signs of something as monumental as a heart attack, cardiologists say they see it quite often.
It happens "ALL THE TIME!!!" Dr. Kenneth Rosenfield, an interventional cardiologist, wrote in an e-mail. "Every week. Seriously."
Rosenfield says a "Hollywood heart attack" -- the kind where you collapse to the ground clutching your chest -- is the exception, not the rule. "We need to do a better job of letting people know what are all of the types of symptoms that can indicate a heart attack," he says.
Smith couldn't agree more. Looking back at her heart attack eight years ago, she now sees she had symptoms for six months and missed them. "My message to everyone is simple: If your symptoms are frequent do not hesitate. Have them checked before it is too late," she says.
Former President Bill Clinton was hospitalized last week and received two stents after he experienced brief periods of discomfort over several days. Clinton, who'd undergone bypass surgery in 2004, said he began feeling tired around Christmas. "I didn't really notice it until about four days ago when I felt a little bit of pain in my chest, and I thought I had to check it out," he said.
The signs that you're having a heart attack -- or that your arteries are so clogged up you're about to have one -- vary from person to person. You can listen to heart attack patients describe what it felt like to them, and the American Heart Association, the National Heart Lung and Blood Institute, and the Mayo Clinic have lists of heart attack symptoms and warning signs.
Here's a list of some of the more common signs:
1. Chest discomfort
While not everyone feels it, chest pain or discomfort is still the most common sign of a heart attack, according to the American Heart Association.
The pain isn't necessarily overwhelming. "It was a relatively mild pain that I kept expecting to go away, but it never did," says Duane Marcus, 56, of Stone Mountain, Georgia, who had a heart attack two weeks ago.
Rolanda Perkins, who had a heart attack just over four years ago at age 39, says at first she ignored her chest pain because she thought it was indigestion. "I figured I could go to the doctor in the morning, but morning came for me at about 3:30 [a.m.] when the pain got worse and I had a shortness of breath," she remembers. "I knew that something was wrong."
In recent years Perkins, who lives in Tennessee, has completed two half-marathons. Now she tells people to listen to their bodies. "My body was speaking to me, and I was not listening," she says.
2. Discomfort in other parts of the upper body
Rob, an Atlanta businessman who asked that his last name not be used, said pressure behind his ears while working out on the stair-stepper was the first sign that something wasn't right.
He was 50 and on vacation at the time, and he didn't think much of it. But when he got back home he also started to experience a bit of tightness in his chest while exercising.
It seemed so strange that he walked into a cardiologist's office without an appointment and insisted on seeing the doctor. He had bypass surgery the next day.
Rosenfield, head of vascular medicine and intervention at the Massachusetts General Hospital, says pain in a variety of places can indicate a heart attack.
"I often tell my patients that they should be mindful of any symptom from the waist up which seems different or unusual," he says, including "heaviness, pressure, squeezing, aching, or discomfort in the chest, back, neck, shoulders, or arms, wrists, elbows, between the shoulder blades, aching in the jaw, throat, or even gums or earlobes."
Of course, discomfort in any of those areas could mean myriad other problems and not a heart attack at all.
So how do you know the difference?
Rosenfield says pay particularly close attention if you have a personal or family history of heart disease or risk factors such as high blood pressure or high cholesterol. Other reasons to be on guard is if the symptoms are particularly intense, happen for no apparent reason, if they get worse with exercise, if they don't go away, or if they go away and come back.
3. Gastrointestinal problems
When Dr. Malissa Wood's father complained about stomach pain and nausea, she paid close attention because he said it felt different from ulcer problems he'd had in the past, and because he had a history of high blood pressure and vascular disease.
Wood, a cardiologist and assistant professor of medicine at Harvard Medical School, made sure her father received quick attention, and it turned out his right coronary artery was 92 percent blocked, requiring stents and bypass surgery.
4. Flulike symptoms
Dr. Robert Superko says he's seen it many times: A patient's routine EKG will show signs of an old heart attack, but when he asks whether the patient has had a heart attack the person says no, adding, "But, oh yeah, doc, last year I had a really bad flu."
Superko, a cardiologist and author of the book "Before the Heart Attacks," says significant fatigue, feeling exhausted for several days, gastrointestinal problems (see above) and a general feeling of not being well can be signs of a heart attack or heart problems -- and they're easy to miss. "You can see how people could just write it off as the flu," he says.
5. Shortness of breath
Shortness of breath can be a sign of a heart attack even if you don't have any chest pain or discomfort.
CNN's Sabriya Rice contributed to this report.