Even in the midst of a second heart attack — this time, it felt like someone was standing on his chest — Conner said he was still in denial.

"I never smoked, heart disease wasn't in my family, I played Division I sports in college, I exercised a lot and I was never overweight," said the 47-year-old, who was helping lift a refrigerator at the time. "I did have high cholesterol, but I decided not to take blood pressure medicine and just work out harder."

After trying to walk off his symptoms to no avail, Conner eventually asked a coworker to take him to the emergency room.

"... the doctor said I would only live until tomorrow morning if they didn't operate then."

Conner's case isn't an isolated incident. From heart attacks and stroke to broken bones and even pregnancies, some people play down symptoms in the belief that such unexpected developments can't happen to them.

"I think people ignore just about everything," said Dr. Paul Katz, medical director of the Washoe Comprehensive Stroke Center.

Here's a list of medical symptoms you shouldn't ignore, according to medical experts.

• Chest discomfort or pain: One of the reasons Conner didn't think much of his first heart attack was because he felt chest discomfort but not pain. Indeed, mistaking chest discomfort from a heart attack for heartburn is a common error, said Dr. Brian Passalacqua, a Reno physician.

To distinguish heart attack chest pains from heartburn, look for accompanying symptoms, Passalacqua advised. These include nausea, feeling clammy and shortness of breath. Chest pains radiating to your jaw, neck or hands also are signs.

• Severe headache: This can signal a stroke or a brain tumor, said Dr. Denise McKee of the University of Nevada School of Medicine.

Distinguishing a headache from stroke shouldn't be difficult, experts say. "We usually say (it feels like) the worst headache of your life," Katz said. For people who regularly have headaches or migraines, a change in your headache pattern can be an indicator, experts say, along with other accompanying symptoms such as confusion or imbalance.

• Breathing problems: These can indicate a heart attack or lung problem, among other things. Breathlessness may be normal during strenuous exercise or even when you're hyperventilating from fear or anxiety. But shortness of breath that's prolonged, severe or sudden is not normal, according to the Mayo Clinic.

• Difficulty speaking, understanding or moving: Sudden difficulty with either speaking or comprehension are telltale signs of a stroke, especially if accompanied by sudden weakness or numbness in areas of the body such as the face, arms or legs. Weakness in one side of the body also is common, Katz said.

• Blood in vomit or stool: Vomit with blood or what appears to look like coffee grounds could indicate an ulcer in your stomach, esophagus or upper intestinal tract, says the Mayo Clinic. Blood in your stool may need attention.

• Severe abdominal pain: This can indicate a host of conditions from appendicitis to gallstones and, in some cases, even a heart attack, Passalacqua said — note if the pain doesn't go away for an extended period of time and is accompanied by other symptoms.

• Blood clots of the leg: Redness, swelling or tenderness of a limb — especially the legs — may be signs of a blood clot, says the Mayo Clinic. Such a clot can be life threatening if it travels to the lungs or brain.