My training schedule for the Chicago Marathon includes three runs of 20 miles each and one run of 22 miles; starting this weekend I've got one of these extra-long runs every other week before beginning my taper (easing off the mileage to be fresh for the actual race).
I got started at 6:15 this morning while it was cool (around 60) and very, very foggy; there were periods of time during the first 6 or 7 miles where I couldn't see more than 10 or 20 yards in front of me. Overall the run went very smoothly, though the last 4 miles were really, really, really, really tough. The pain and tiredness in my legs was like nothing I've ever experienced before and I also found it hard to concentrate - for a while I couldn't remember whether we live on Lake Drive North or North Lake Drive....
I'm very pleased with the final results: 20.75 miles in 3:30:54 - good for a 10:10 minute/mile pace. The pace of my long runs has gone from 10:36 to 10:24 to 10:10 in the last month, so I am definitely making progress. Previously, the longest distance I'd ever run was 18.35 miles; the new record is very satisfying but I know I've got to set a new one at least twice more before this process is over.
One more thing to note: on each of my three long runs now I've gotten this sensation that I guess could be what people describe as a runners high. It's a moment in a run where all of these feelings come together at the same time - tiredness, pain, exhilaration, a sense of progress, rhythm, and above all, the confidence you're going to finish what you set out to do in spite of the hurt. Anyone else ever have that experience?