I finally was able to resume running today! I managed to run 4.25 miles - took about 34 minutes, and holy cow - I'm shocked by how much "capacity" I lost after not being able to run or do much for nine days.
So, my advice to anyone that's working on their own diet/exercise/training programs: never quit. Never stop. Don't take any significant time off. No matter how much you want to talk yourself into "taking a few days off" - don't do it. Unless of course you're nursing an injury or something like that... otherwise, stay at it. Be relentless.
I looked back at my training logs (via my GPS watch), and tried my best to recall all of my running/riding/training activities, and quickly realized that since January of 2008, I've probably only "skipped" two consecutive days of training once or twice. Taking nine days off really put a dent on my capacity; if there were anything I could've done to get back into things earlier, I would've. But based on how I had been feeling just 3-4 days ago, I consider myself extremely fortunate to have been able to run today.
I woke up (via the cat - argh) at 7:00, put on my running gear, took a long stretch (about 25-30 minutes worth), and hit the road. My legs felt sluggish and heavy. I didn't have any feeling of "flow" - every stride felt labored. My breathing was decent, but after about the three mile mark, I started to get a bit of a side/diaphragm ache. I wanted to start walking, but I forced myself to keep going. After the run was finished, I stretched for another 15 minutes or so, and then took a shower.
I'm hoping things will restore themselves in short order, because based on how I felt today, it seems as if I "lost" a solid 6-8 months worth of training effort over a period of 9 days. It's absolutely crazy how fast your body can give-up aerobic capacity... what takes years to gain can literally dissolve over a period of days.
So, I'll say it again: no matter how cold the weather is, or how tired you feel, or how busy you may be, keep at it. A day off can easily turn into two days, and three, then four, and before you know it, you'll have lost much of what you worked so hard to gain. And then it's depressing because it feels like you're "starting over," and so it's even more tempting to quit. Train smart and keep at it.
I'm going to get up early every morning of this week and do 4.5 - 4.75 miles per day; I'll keep the mileage low for a bit, or at least until my legs feel a little more limber. I'd hate to suffer a stress fracture or some kind of dumb injury... At least the weather is supposed to be decent this week - it was actually "hot" today; nearly 40-degrees! I took off my hat and gloves about 3/4 of the way through - I was getting too warm. :-) For comparison, it was 67F in Austin today.