igh Heart rate

Im a fit 42 year old temale triathlete. Before I was a triathlete I was a long distance runner and ran many marathons.
Last year I competed in some hakf ironman events and trained hard all year. After the World Champs in C learwater Florida in Nove, I suddenly found my HR going up to 160 when I started to run. Im running easy and slow and my HR is between 160-170, all the time. I will stop to walk and it takes 2 minutes for it to drop to 130 and as I start running again it goes straight back to 160...
I eat well, I am in good shape but this is making me feel awful and Im unable to train.

The same thing happens in a spin class. My usual heart rate would be at 130 and now its at 160 within minutes of strating to spin, without exerting much effort at all.

[Encephalomalcia]

My heart rate does this when I walk upstairs.  When I had my stress test it was up to 180 in no time at all and the nurses made a comment about it.  I have an adrenal problem and that may be what is going on with you also.  I believe there is more of a chance of this problem as we get older.  I am 44.  Ask your doctor about it.