
Two days in a row, on different treadmills and once with a
heart rate monitor, I have seen that about 15 minutes into a run my
heart rate has gone from a 200+ down to a 30-50. Today, which is when I added the monitor, it showed that I stayed at a 30 for almost a minute, then went to a 0 for a couple of seconds, and then slowly climbed back up to a 40, 41, 50... then it spiked again at a 200.