In nearly 100% of all cases of panic attacks, the sufferer over breathes, whether they are aware of it or not. This is called hyperventilation, the symptoms of which are listed below.
----------- Symptoms commonly encountered in chronic and acute hyperventilation -----------
Cardiac:- Palpitations (or increases heart rate), missed beats, tachycardia (or rapid heartbeats), angina (or restricted chest/pains), atypical chest pain, dull precordial or lower costal ache (or pains in chest), vasomotor instability (or blood vessel fluctuation).
Neurological:-Dizziness, faintness, visual disturbance, migraine headache, numbness, paresthesia of limbs face or elsewhere (or inability to move), intolerance of bright lights or loud noise.
Respiratory:-Irritable cough, 'asthma', tight chest, excessive sighing or yawning.
Gastrointestinal:-
Dysphagia (or difficulty in swallowing), dry throat, flatulence and belching, aerophagy (excessive air swallowing), upper abdominal distress, globus (or swollen throat).
Muscular :-Cramps, diffuse or localized myalgia (or muscular pain), tremours or coarse twitches, rarely tetany.
Psychic:-Tension, anxiety, 'unreal' feelings, depersonalization (not feeling real, or oneself), hallucination, fear of insanity, panic attacks, phobic states.
General:-Weakness, exhaustion, lack of concentration and memory, sleep disturbance, nightmares, emotional sweating (under arms and palms).