Intervals, or, hitting the "puke zone"

Ok, I confess, I'm a slow runner. My body just wasn't made to go quickly, no matter how hard I try. I'm too big, too heavy, to un-aerodynamic to create much speed. It's hard to pick my feet up quickly, or very high.

But I do try. My "coach" likes to remind me that occasional speed workouts are good for the soul. Or is that sole?

So tonight after work I hit the track for my first real speed workout of the year. I think I've done some 220 repeats earlier, but I vaguely remember quitting after only a few. It just hurt too much. Tonight, I didn't quit. And no, it wasn't a killer workout compared to some folks, but this is the Land of No Comparison, remember? It was a toughy for me, I pushed myself, and that's all that matters.

Can some helpful runner, tri-er, overachiever remind me of why I'm doing these things?

The workout:
1x880 warm up
8x440 (alternating "fast" and "slow")
1x880 cool down

3 miles. I only walked the last "slow" lap, and never quit on any of the "fast" laps. And yes, it was in the back of my throat. Twice.