Nighttime (nocturnal) panic attacks can occur with no obvious trigger and awaken you from sleep. As with a daytime panic attack, you may experience sweating, rapid heart rate, trembling, shortness of breath, heavy breathing (hyperventilation), flushing or chills, and a sense of impending doom. These alarming signs and symptoms can mimic those of a heart attack or another serious medical condition. Although panic attacks are uncomfortable, they are not dangerous.

Nocturnal panic attacks usually last only a few minutes, but it may take a while to calm down and go back to sleep after you have one. People who have nocturnal panic attacks also tend to have panic attacks during the day.

It's not known what causes panic attacks. Underlying factors may include genetics, stress and certain changes in the way parts of your brain work. In some cases, an underlying condition, such as a sleep disorder or thyroid problem, can cause panic-like signs and symptoms. Talk with your doctor about your symptoms and whether you need any tests for a possible underlying condition.

Treatment — cognitive behavioral therapy or medications or both — can help prevent panic attacks and reduce their intensity when they do occur.