I ran the 2024 Chicago Marathon in 3:54:29. Then I basically stopped running for a year.
Not dramatically, not all at once. Life just kind of took over the way it does, and somewhere in 2025 running fell off the list. By January of this year I'd gone from someone who finished a World Marathon Major to someone who was winded climbing stairs. Not great.
The thing that got me back was signing up for the Shamrock Shuffle. Eight kilometers, downtown Chicago, third week of March. Low enough stakes that I wasn't scared of it, but real enough that I actually had to train. I spent February putting in just enough miles to not embarrass myself, and on March 22nd I stood at the start line for the first time in over a year.
I wanted to go sub-42:00. Went 40:45 in 41°F weather with 20mph wind. Ran a negative split, which I honestly didn't plan. It just happened. Something clicked during that race that I hadn't felt in a really long time, this sense that the aerobic base I'd built in 2024 was still in there somewhere, just waiting. The Shuffle confirmed it.
March: Getting Back On the Horse
March was about 30 miles total, most of it built around race week. After the Shuffle I took a few easy days and then started actually building. The first real long run was March 28th, 7 miles out on the Illinois Prairie Path west of Elmhurst. That trail is my home turf. It's flat, mostly shaded, no cars, and you can run forever out there without dealing with traffic lights or road crossings. If you're a western suburbs runner looking for long run territory, the Prairie Path and the Great Western Trail loop through Glen Ellyn is worth knowing about.
The data side of March was encouraging. My Garmin VO2max hit 47.79 the day after the Shuffle. One race effort and a week of resumed training and I was already back near where I'd been in 2024. That told me something useful: the fitness doesn't disappear as fast as you think it does when you stop.
April: First Real Month of Training
April felt completely different from March. 106 miles, first 100-mile month of 2026, and for the first time the training had the texture of an actual block rather than just getting out the door.
I spent the first week of April in Florida running in 70°F humidity, which was a rude awakening. I was running 9:39 miles at the same cardiac output that produces 9:11 miles back home in Illinois. Every run felt harder than it should and I kept second-guessing myself, wondering if something was wrong. Nothing was wrong. Heat and humidity just impose a real tax on pace. I now have the data to quantify that tax at roughly 44 seconds per mile at identical effort. I'll use that number a lot this summer when the Chicago heat sets in.
Coming back to Illinois on April 6th was one of those rare moments where the data matches exactly what your body is telling you. First run back, same effort, and I was 44 seconds per mile faster at meaningfully lower heart rate. The fitness was there the whole time.
Mid-April I put in the first threshold session of the block: two miles easy, three miles at 8:00-8:05 pace, one mile to cool down. It held. HR was appropriate, RPE was where I wanted it, and something shifted after that workout. The training stopped feeling like base building and started feeling like race prep, which is a different thing.
The best single run of the two months was April 26th. 12 miles, 8:34 average, with the back half at 8:17. Mile 11 came through at 7:51 at 157 bpm. That's essentially race pace, happening naturally without being chased, with 33% stamina remaining at the end of the run. Runalyze had been projecting me for a 1:52 half marathon. After that run I had serious doubts about that number being a ceiling.
The Numbers
Resting HR dropped to 47 bpm on April 21st, lowest of the block and lower than my baseline from January. HRV stayed in the balanced range throughout with no concerning dips. VO2max went from around 46 at the March restart to 47.79 by end of April. The aerobic efficiency trend across the two months was clear: same pace, lower heart rate, week over week.
One gear note worth mentioning. I'd been running with a COROS armband HR strap that had been dropping signal all through the Florida week, corrupting multiple runs worth of heart rate data. Mid-April I switched to the Polar Verity Sense armband and got clean signal immediately. Small thing but it matters when you're training by HR.
What This Was All About
The Chicago 13.1 is June 7th. That's 18 weeks before the October 11th marathon, which is not a coincidence. The Distance Series is designed so the half sits almost exactly at the start of a proper marathon block. Run the half, take a few easy days, start week one.
March and April were really just about answering one question: is the fitness still there after 15 months of near-nothing? The answer turned out to be yes, faster than I expected. Now the actual work starts.
May recap coming next week before the 13.1. That one has more to say.