HRM off - possible interference? Any ideas?

irisia99

I have a Garmin Forerunner 210. I've been doing a lot of spinning recently and my heart rate is usually averages between 154-166 bpm per class with a max of 181-185 bpm. (I'm comparing my last 6 spinning classes to get these numbers). I took a spinning class last night at 6pm. Today, I took another spinning class at 10:30am. My HRM seemed to be giving me whacky numbers and I don't know why. This morning my average HR was 171 bpm and my max was 200 bpm!!! The room was warm and I was completely drenched at the end of class but I didn't feel like I was working THAT hard. Don't get my wrong, I was definitely breathing hard and sweating but it was comfortable-to-uncomfortable exertion. I can't maintain 200 bpm for more than 1 minute - if I could even get my HR that high! I didn't feel like i was going to die or anything during class.

Is it possible there was some interference this morning? I wasn't sitting that close to anyone and the person nearest to me (2 bikes away) wasn't wearing a HRM that I could see. My HRM worked perfectly at 6pm yesterday. I don't think it's a batteries issue. Would could make my HRM spike like that? It was a new instructor for me but still - I just don't think my HR was really at 200 bpm. I guess the real reason I care so much is bc the HRM uses my HR to calculate my calories burned. I want to make sure it's accurate.