If you experience four or more of these symptoms, you could be having a panic attack. As these symptoms multiply, you may feel an impending sense of doom or a loss of mental control. Gradually, these feelings and symptoms will subside. Once the attack has passed, a feeling of fatigue may set in.

How long do panic attacks typically last?

Panic attacks often begin suddenly and without warning. Once they start, they tend to peak within 10 minutes and last for a total of about 30 minutes. However, no two panic attacks are exactly alike, and some patients have reported panic attacks that last for several hours or even an entire day. Panic attacks can strike at any time during waking or sleeping hours, and a high percentage of those affected report that these attacks awaken them in the middle of the night.

What causes a panic attack?

Although the exact cause of panic attacks is not yet understood, stress and various biochemical factors are believed to contribute to the attacks.

Some experts have speculated that panic attacks may be related to the body's "fight or flight" response. This response occurs in the sympathetic nervous system when the body faces danger. Adrenaline, also known as epinephrine, is a chemical secreted by the body in response to stress. When the body faces danger, adrenaline and other hormones are released, allowing the body to either fight or flee from the danger. Researchers believe that during panic attacks, an unknown trigger may activate this response despite the fact that no danger is actually present. Other researchers have cited a similar "suffocation alarm" in the body that falsely indicates that death is imminent, triggering an attack.