A panic attack is a sudden and acute feeling of anxiety. Physical symptoms of panic attacks include trembling, disorientation, nausea, rapid, irregular heartbeats, dry mouth, dyspnea, perspiration, and dizziness. A panic attack's symptoms are not hazardous, although they can be scary. They can make you feel as if you're having a heart attack, about to collapse, or about to die. The majority of panic attacks last between five and thirty minutes.