Perplexing pulse

I've been taking my pulse periodically through the day the past few days just to see what sort of pattern (if any) there is. I know it's normal for pulse rate to vary through the day, I just think some of the behavior of my pulse rate (and others with CFS who have done the same thing) is a bit bizarre.

For example... I forgot to take it when I first woke up this morning before getting up. But, after getting up, going to the bathroom, walking to the kitchen, getting a frozen breakfast from the freezer, getting a paper plate, putting the food on the paper plate, and putting it in the microwave... my pulse was 116.

My target heart rate for exercise is supposed to be about 111-160. I hit that with *normal* morning activity. No caffeine, nothing to drink, I wasn't stressed...

And I had no trouble at all finding a pulse to measure.

Now, though.... I'm feeling a fatigue slump coming on -- my usual afternoon thing. You'd think I don't *have* a pulse, with how hard it is for me to find it right now. After quite a bit of hunting, I found it and it's 80. This is *with* caffeine, having eaten, but granted I've been sitting on the couch relaxing for a bit.

My resting rate seems to be between 75 and 82.