A more extreme example of an anxiety disorder is that known as Panic Disorder. People with this issue find themselves suddenly and unexpectedly in a fight or flight situation of extreme fear and a feeling impending doom for no apparent reasoning. Many things can trigger this, but what is happening is the body is taking any stressor and immediately jumping into overdrive mode to protect itself. Symptoms for those suffering from this include pounding heart beat with palpitations, sweating and shaking, and a sudden shortness of breath where one feels they cannot breathe. Intense fear overcomes them and they may feel out of control, and when it finally ends they fear the next one and what may trigger it which can cause a feedback loop of intense fear and paranoia.