I didn't know I'd be wiped out so long after Ironman (my running partners are still complaining that I'm breathing too hard during "easy" runs). So I picked 7:05 pace, 18 seconds slower than last year's, but still a challenge. For heart rate I chose 165 bpm. I figured I did Ironman Canada at 160 bpm and Ironman Hawaii at 165 bpm so it should work for a little 30k run. The first few miles were fun, I talked to friends as they asked me about Ironman... and then preceded to leave me in the dust. I joined a pack as we took turns blocking the wind but soon they pulled ahead, too. My 7:05 pace didn't change for 16mi. but the effort sure did.

After 5mi I was above 165 bpm so I set the upper limit to 170. After 10mi, I had to really work hard so I changed the limit to 175 bpm. I hoped I could wait till 15mi, but at 14, to keep the pace, I had to push the pedal to the floor, increase the heart rate to 180, and pour on more fuel (gatorade, energy gel, and water).

Heart rate is like an internal tachometer. We all have different "red-lines" (max heart rate). Mine is about 193. Below 85% of max, or 165 bpm, I'm running aerobically and getting enough oxygen to the muscles to operate cleanly. Because the muscles aren't recovered, they require more oxygen and higher heart rate. Above 165, the process turns anaerobic and develops lactic acid which builds up, clogging the engine.

Well, by mile 16, my engine was full of lactic acid and began slowing down, bringing the heart rate down, too. At this point there's nothing you can do. It's like biking up a steep hill and looking down to discover you have no more gears to shift into. Like a car out of gas with 4 flats, I coasted to the finish. The legs are hurt'n but I appreciate the knowledge gained.