Heart rate stops monitoring in running app

Hi everybody,

when I use the running app of my apple watch, the app stops measuring the heart rate after a few minutes (can be 4, can be 10 minutes). I never had this issue in the past and I'm using the watch since almost 2 years for running. This issue appeared maybe three weeks ago before I did the last recent update of my watch.

After the run I tried the heart rate app and after several attempts it worked again.

For me this looks like a hardware failure, but maybe anybody has made similar experiences and therefore another advice for me?

Thanks in advance,

Christian