It is odd, I've reduced my HR numbers overall after 7 months of a dramatic diet change and adding more running to my work-out week. My peak and zones seem to have dropped about 20 points across the board, resting HR dropped about 4 points. I'm not complaining, but the why is a mystery. There are so many variables; even breathing through your mouth vs. nose is argued to increase your HR by as much as 10 bpm.

Am reading about the Tarahumara, .. a marathon a day on little more than corn beer...and no power bars.