having a heart rate of 200 is not normal under any circumstances. this can be due to a condition called " supraventricular tachycardia", which is most common in young females. but it is not easy to diagnose it, and should not be treated until confirmed diagnosis is made. to make confirm diagnosis we got to have an ECG recorded during the episode of increased heart rate. Get a 24 hour holter monitoring test done. here a small ECG machine is tied to your chest which records ECG continously for 24 hours, whatever you do. If there is supraventricular tachycardia machine will record it and it can be cured completely.