my58vw

Something is wierd today, and I am a little confused on this issue, my HR is way low...

I started my Wednesday interval session as normal on the trainer for LT work. I warmed up for 20 minutes and noticed that my HR was low, like riding a 39 - 14 and my HR around 120... about 10 beats below normal. I though my HR monitor was on the fritz like it usually can be but I verified and it to be right on. I verified it again after resting and it was only 1 beat off from measured.


I did my warmup and started into my first LT interval, my HR slowly went up but in the usual gear I do it in I was not really working all that hard, pushing a 53-17 at 90 RPM. My HR was around 147 at the time and there was no labored breathing, no burning but I was putting alot of force (percieved exertion) into the pedals. I thought something was wrong with the trainer so I upped the tention on the wheel and started again, a little more force required but the HR was sticked right were it was, maybe at 149 BPM now. My LT is 166 BPM now and I still was not close, and still no labored breathing indicative of LT. I pushed a higher gear and my HR went up a little but not much. I upshifted again and started getting a little uncomfortable breathing but not bad, but I was in such a high gear I could not push hard enough. I stood up and mashed as hard as I could and my HR went up again to about 159 BPM but still no great labored breathing. Finally my legs were tired and the interval was over. After 1 more I was so tired quad wise I stoped.

Is this what happens when your LT goes up? It seems like my limiter right now is power and not HR by this session, wierd. Last night I felt very simular, it was not until I really pushed hard that I went anarobic and it was more tiredness in the legs vs HR.

Any interpretations