[pavulon]

I'd verify the accuracy of the watch (check it with your finger) If it is accurate, I'd wonder how you feel when your heart rate is that high (do you feel winded?). A few things can drive your heart rate beyond an expected rate w/ activity (like mild-moderate anemia, lung disease...). All things being equal, I think you're right for being concerned about a heart rate that high. It may turn out to be nothing but if it happens frequently and seems to be more than one might expect, consider looking for a cause.