Update

In chronological order from Saturday to today:

Saturday
Stacey and I drove out to Frisco for a trail run. We selected our route from a hiking book, which described the trail as moderately uphill for the first 2 miles and then steep for the next 2 miles. Well, the first 2 miles were not easy. The gradient and the altitude combined, perhaps along with some residual fatigue in my body, to make for a hard run. I ran a bit over 30 minutes (pretty much all steep uphill) before turning the run into a hike with Stacey. Hiking must work slightly different muscles than running or biking because I am always sore after a hike. Even this 2.5 hour jaunt fatigued me enough to effect Sunday's run.

Sunday:
My legs were dead at the start of this run from Saturday's jog/hike. I ended up doing 15.5 miles in 1:50. The first 11 miles were at just under 7:00/mile pace with a HR starting at 150 and building to the lower 160s. At times I was cruising at 6:20 pace without much effort (okay, so that was slightly downhill aided, but not much). After 11 miles, my PE was starting to climb to hold my pace, and I didn't want to dig too deep. I opted to jog home the last couple of miles. Once home, I had to relax a good hour before being much use for anything.

Monday:
Off. I was exhausted after work and yesterday's run. I listened to my body's signals and rested to absorb my weekend's efforts.

Tuesday/Today:
10.5 miles in 1:15. 7:18/mile at 148 bpm. A nice and easy run. Harder than a jog, but very low perceived exertion. The only issue is that around 8 miles my legs begin to tire a bit. I think more running consistency and volume will solve that problem.

The issue with this workout is that it isn't hard, but it isn't easy. I may follow it up tomorrow some harder intervals, but if I feel tired I'll go very easy tomorrow and then hard on Thursday.

On a final note, after a successful month of 3 days on, 1 day off, I'm switching to 4 days on, 1 day off. The goal is to run 6 days a week within the next few months (no hard deadline), and then up my running frequency to 8 times per week with one day off.