A panic attack is a period of intense, often temporarily disabling sense of extreme fear or psychological distress, typically of abrupt onset. Though it is often a purely terrifying feeling to the sufferer, panic attacks are actually an evolutionary body response often known as the fight-or-flight response. Symptoms may include trembling, shortness of breath, heart palpitations, chest pain (or chest tightness), sweating, nausea, dizziness (or slight vertigo), hyperventilation, paresthesias (tingling sensations), vomiting, and sensations of choking or smothering. During a panic attack, the body typically releases large amounts of adrenaline into the bloodstream. Many first time sufferers of a panic attack believe they are dying or going insane. It is a feeling that cannot be described until one has had an attack. Many often say panic attacks are one of the most frightening experiences in their lives. Repeated and apparently unprovoked panic attacks may be a sign of panic disorder, but panic attacks are associated with other anxiety disorders as well. For example, people who suffer from phobias may experience panic attacks upon exposure to certain triggers. People with panic disorder often can be treated with therapy and/or anti-anxiety/depression medication. A panic attack typically lasts ten minutes.