Punking out

Last night was the first time I've punked out in a workout in a long, long time.  It was cold (low 40's) and monsooning out, so I opted to do my tempo workout indoors on a treadmill (which sucks).  The plan was to run 1.5 warmup, 3x 1mile @ 10k pace, and 1.5 mile cooldown.  I followed conventional wisdom and set the treadmill at a 1% grade to make the pace more equivalent to running outdoors.  For some reason, this workout was tough!  I made it through the first mile wondering if I would be able to finish the workout.  I made it through mile 2, and my heartrate was way higher than it should have been at 10k pace (I thought- I'm not actually sure what it's supposed to be).  On my 3rd mile, I was miserable just starting out, and on a treadmill you don't have the option of slowing down to cheat a bit (without making a conscious decision to do so).  I told myself to just run 1/2 a mile, and then if I wanted I could stop (knowing that at that point I would talk myself into going farther).  At 1/2 mile, I talked myself into running to 3/4 mile, but I felt like I was on the final sprint of a race!  I was gasping; I was dying!  At 3/4 mile I knew I was close to the finish, but really didn't think I could go any further, and I ended up pushing another minute or so to 0.85 mile, and then I hit "stop".  I hit "stop"!  I was dying; I was done; but I was so disappointed in myself for giving in.  (I did finish my cool down afterward)

I'm not sure why that workout was so tough.  My Garmin footpod said I was running 6:03 min/mile instead of the 6:26 to which I set the treadmill, but which one was accurate? (I'd guess the treadmill)  My heart rate when I hit stop was 190, which seems a little high for a training run, but I looked back through my run data from the last couple of months and realized that I haven't really been wearing the monitor for speed work or tempo work, so I have no real basis for comparison.  On my long runs at marathon pace, my heart rate topped out around 172, but that's not really a comparable intensity.  Maybe I was feeling the effects of accumulated fatigue from workouts earlier in the week?  Or maybe it was just a tough workout I was going to have to gut out to make it through.

Anyway...  I was pretty disappointed in myself for pulling the plug in the middle of the workout.  It sounds like such a minor thing, but in training it's the discipline to do what you set out to do that forces you into improvement.