My half marathon progression

I'll start this timeline back in 2003-4. I was a graduate student at Clemson fighting adrenal fatigue and chemical instability. I only trained about 20 MPW because of time constraints but almost all of it was hard. I estimate based on a couple of 10 mile training runs @ 7:40 pace, I was good for a half in the low-mid 1:40s. I only raced once in those 2 years (a 10K in 45:04). In 2005, the bubble burst and I endured a living nightmare for more than a year. I needed powerful stimulants just to function at a basic level and crashed after 2-3 miles of slow jogging on a good day. On a bad day, a trip to the grocery store would leave me exhausted.

2006: Diagnosed with full blown adrenal exhaustion. Limited to walking at first but progressed to walk/jog then a 9 minute pace in training. Progress was very rapid.

2007- Debuted at Seaside with an exhausting 1:59:37 half in which I had to walk/jog the last 5K. Soon after, I was diagnosed with numerous neurotransmitter imbalances. Again, improvement was rapid but I was VERY unstable. In Memphis 9 months later, I had improved to 1:48:17 without much additional training.

2008: Continued to improve but remained unstable. I improved at every distance but only raced one half (1:42:50 in Chicago). Finally, I was at a level comparable to before the crash. A sub-1:40 was looking likely but 10 minutes faster than that was unthinkable.

2009: A great year for me in almost every way even though there were quite a few rough stretches. Set a massive PR at Mercedes in February (1:36:16). For the first time, I began to think that 1:30 might be possible after all so I set it as my lifetime goal. I followed that one with another strong PR in Baton Rouge 10 months later (1:32:57)

2010: This was a down year for my running. I suffered 2 significant injuries but raced 3 halves that ranged from 1:34-1:42.

2011: Squeaked out a baby PR in Chattanooga in February (1:32:49) but the breakthrough came after quitting soda for good. I set back to back PRs in October with a 1:31:32 in Montgomery and a 1:31:02 in Columbus. My final attempt was a disappointing 1:33 in Arkansas.

2012: 1:28:12! Victory. Can I improve on that? I believe that I can but anything beyond it is a bonus. This is nothing short of a miracle recovery!