<s>[INST] walking down stairs  and  heart beating so fast could not count it-- felt like  in my throat and upper chest NO history of high  BP  it converted back to normal rhythm in about 3 to five minutes  is this a panic attack or heart disease  iam a 60 year old healthy female--- only risk factor is over weight BMI 29-30 [/INST] Mostly your body is not used to exercise,  hence the heart rate Response is higher,  however if persistent,  associated with chest heaviness Or breathlessness,  get a stress test done Regards Dr priyank mody </s>