Recognizing the signs of a heart attack is the first step to lessening heart damage and saving your life when seconds count. Common warning signs of a heart attack include chest pain and pressure, unexplained shortness of breath, cold sweats and even nausea or vomiting. If you experience any of these symptoms, call 911 immediately. When you’re still conscious and while waiting for EMS to arrive, take aspirin if you have it. A normal dose of aspirin (325 milligrams) works by slowing the blood’s clotting ability and minimizes the size of the blood clots that may have formed.