I just was PMing with a friend who is facing the possibility of some serious life-threatening information. He is already having sleep disruption and anxiety. As a preventative measure, I shared with him what a panic attack feels like in the beginning... so that if he should start to careen down that slippery road that he would know what to do.
Likely, if you know what one is and possess the tools to address it in advance, you will be far ahead of most people in dealing with it and can even prevent it from developing.
Panic attacks usually begin abruptly, and may reach a peak within 10 minutes. It might feel like:
a heart attack
a "flashing vision"
feeling faint or nauseated
a numbing sensation all over
tunnel vision
labored breathing or hyperventilation with the feeling of not being able to get air
trembling, heart palpitations, chest pain or tightness,
hot or cold flashes, sweating, dizziness, light-headedness,
tingling sensations, sensations of choking or smothering
difficulty moving and disassociation
A panic attack is a response of the sympathetic nervous system.
Often a panic attack is incorrectly self-diagnosed as a heart attack and the sufferer ends up in an emergency room. It is not unwise to allow an electrocardiogram to rule out a heart attack. Better safe than sorry.