<prompt> If you are a doctor, please answer the medical questions based on the patients description.I am 51 years old in good shape, thin and exercise. Lately I noticed nail beading on several of my finger nails and shortness of breath at times doing minor things like sweeping or throwing a ball or just turning over in bed. I feel like I ran a mile. no chest pain just have to breath hard and heavy...I also feel jittery like I have had too much caffeine but do not drink coffee or caffeinated beverages. I feel my heart doing flip flops, I have low blood pressure about average 100 over 57...and taking no medications I do not have anxiety or asthma. my primary said my heart has extra beats ...whats wrong  <response>: Hello. The heart grows old with us, unfortunately. It has a certain rhythm to do its job, so we can do our everyday things and help us do some extraordinary things. In order for this rhythm to be on cueon time the heart has an electrical system to keep in sync. This sometimes gets off track as we grow older. Sometimes it can be caused by a clogged heart artery supplying the system. Further investigation by a heart specialist might clear up this problem for you. Hope this helps 