<s>[INST] as of the past few days, i am experiencing rapid heart beat.  it was short at first but has increased in duration to about 10 minutes at a time.  when it occurs, i am not doing anything strenuous.  i am 36 and in relatively good health.  is this something i need to worry about? [/INST] Dear- thanks for using our system. Rapid heart beat can be secondary to multiples causes. It is important to find out if the heart rate is more thatn 100 per /min and if it is regular or irregular.The best way to find out is taking your pulse and having an electrocardiogram. Medical conditions as panic attack or anxiety, hyperthyroidism, caffeine intake , are some examples of rapid heart beat. You need to see your doctor for a checkup, electrocardiogram and 24 hr holter monitor trying to identify why type of arrythmia you have. Some valvular conditions as mitral valve prolapse can give you rapid heart beat too.I hope that my advise has been helpfulDR.Sara </s>