Week Nine, Monday - Heart Rate

I've read some confusing articles lately about heart rate and anaerobic and lactate thresholds. I was surprised to find I was so uninformed, since I try to understand the basics of anything I'm doing to my body. I try to stay at 75%-80% of my max heart rate for a good portion of my workout and I can do so easily, returning to a resting heart rate within minutes of slowing and stopping. It's much harder for me to stay at 60% - 70%, since I tend to drop right back into resting at the slightest hint of a slower stride. Logically, I know that working out at a higher intensity burns more calories (let's face it, this is my principal motivation for exercise), but it seems that in the past week I've seen cautionary notes in more than a few places warning that staying at 80% will burn blood sugar and make the heart more efficient but that you've got to stay lower to burn body fat. And, as usual, I don't seem to have a gear between go hard and go home. I can't seem to find a conclusive answer, only experts that fall into advocates of a fat burning zone and scoffers at said zone. I try to convince myself that my underlying philosophy is the only one I need to worry about - the activity is what's important; doing something is better than doing nothing - but my tendency to do everything as efficiently as possible makes me wish I had a bottom line/final answer/certainty. You can tell I'm not the most easygoing sort, can't you?

In other news, don't take up shift work. It makes running much harder than it needs to be.