Heart Rate spikes on iwatch 6

heart rate spiking up unexpectedly on iwatch 6

i purchased and iwatch 6 only three months ago. Just for fun, today I was exploring features and I found the heart rate notifications. I was alarmed when noticed pulse rate spikes from 75-80 up to 130-160 during the day as well as at night when the same watch was telling me I was in deep sleep. I called my doc, run many tests and they all came back normal. I called Apple support and they suggested to send the watch to the “depot” for hardware testing. Two days later the watch came back with the message “can’t reproduce the issue” or similar. Back to Apple tec support again. This time they asked me to pair the phone from the back up (no improvement) and then once again set it up as a new watch (no improvement). This afternoon I was taking a gentle walk and suddenly got readings of pulse spiking from 87 to 177!!! I’m calling Apple again tomorrow. I wander what they’ll suggest this time. Any suggestions anyone? Dan