Some people experience what is referred to as limited-symptom panic attacks, which are similar to full-blown panic attacks but consist of fewer than four symptoms. Although anxiety is often accompanied by physical symptoms, such as a racing heart or knots in your stomach, what differentiates a panic attack from other anxiety symptoms is the intensity and duration of the symptoms. Panic attacks typically reach their peak level of intensity in 10 minutes or less and then begin to subside. Due to the intensity of the symptoms and their tendency to mimic those of heart disease, thyroid problems, breathing disorders, and other illnesses, people with panic disorder often make many visits to emergency rooms or doctors’ offices, convinced they have a life-threatening issue.