My last few runs I've noticed a Heart rate spike in the 180s for about 5 minutes at the beginning of all my runs. I'm usually running slow and downhill at this point. The rest of my run (except for a few uphill sections) is in the 140-150 range. Any ideas?
1. This happens not always. Sometimes, around 15 minutes, I do have a higher heart rate. But then suddenly, I do have a high drop of the heart rate, which then is very constant. From my experience, this is not a normal case that my heart rate drops by 20 bpm within 10s or so and then have a constant lower heart rate (eg. 150bpm to 130 bpm without changing pace)
2. I exactly feel the same at the beginning (breathing, etc.) as well as after the drop of the heart rate.
Therefore I am pretty sure that it is rather an device issue than my heart.
