Question about HRM

schlieffen

I bought a Polar F6 HRM this past weekend, and I'm loving all the features. However, I wore it when doing one of the 30 day shred exercises and it kept reading zero or it would fluctuate a lot. I figured maybe I didn't have it on quite tight enough to stay in contact with my skin. So this morning I went wogging (hehe, the word makes me giggle everytime! :laugh: ) with the chest strap on a little tighter. I've been doing interval training (60 sec at 3.0mph then 60 sec at 5.8mph) on the treadmill at the gym for the past week without much difficulty. This morning it was outdoors (flat terrain, paved trail) at 60 sec run, 90 sec walk (and a shorter time than I normally go at the gym) and it was brutal! I found it harder to breath and afterwards it felt like there was a lot of pressure on my chest right where the monitor was. I'm wondering if it was simply too tight, or is there something going on that I should be worried about? Has anyone else experienced this?