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The Chicago Marathon Expo Trap: 9 Things to Never Do Three Days Before Race Day
Months of training can collapse in 72 hours. Here are nine Chicago Marathon expo and race-week mistakes coaches see every single year.
The Chicago Marathon expo at McCormick Place is one of the largest in the world.
More than 50,000 runners pass through it in three days. Free samples, flashy booths, discounted gear, celebrity coaches giving talks every half hour.
It is also where the race quietly ends for thousands of people before they ever reach the start line.
The 72 hours before a marathon are not training time. They are protection time. Here are the nine mistakes coaches see every single year, and how to avoid each one.
The Nine Mistakes That Ruin Race Day
1. Walking the expo for three hours
The expo is big. It is tempting to see everything. Doing so puts six to eight extra miles on legs that need to be fresh.
Have a plan before you arrive. Grab your bib, grab your gear check bag, visit two or three booths you actually care about, and leave. Thirty to forty-five minutes is enough.
2. Trying new nutrition from the sample tables
Every expo booth hands out gels, chews, bars, and powders.
Every one of them promises to be the fuelling breakthrough you have been missing.
None of them have been tested by your gut on a 20-mile run. Race day is not a laboratory. If you did not train with it, do not race with it.
3. Buying new shoes to race in
The super shoe you spot at the expo looks exactly like the one that pros ran a world record in.
It may genuinely be faster. It is also unfamiliar to your feet, your ankles, and your calves.
The rule is non-negotiable: nothing new on race day.
Not shoes, not socks, not shorts, not even laces. If you need shoes for a future race, buy and break them in later.
4. Over-hydrating the day before
Many first-time marathoners interpret "stay hydrated" as "drink constantly."
The result is pale yellow urine every 30 minutes, washed-out electrolytes, and bad sleep.
Drink to thirst. Add a pinch of salt or an electrolyte tablet to one glass of water in the afternoon. That is enough.
5. Changing your pre-race dinner
Chicago has incredible food. Deep-dish pizza, authentic Mexican in Pilsen, Thai in Uptown, pierogi in Ukrainian Village.
None of it should be new to your digestive system the night before the race.
Eat the same pre-race dinner you have eaten before your best long runs. The novel meal can wait until Sunday night, when you have earned it.
6. Scrolling race predictions and weather forecasts obsessively
The forecast will change six times between Thursday and Sunday.
Checking it 20 times a day does not change the weather. It raises cortisol and wrecks sleep.
Check the forecast once in the morning, once in the evening, and plan one hot-weather kit plus one cool-weather kit. Then stop looking.
7. Trying one last "shakeout" workout to feel sharp
A 20-minute easy jog with a few strides is a shakeout. A 45-minute workout with tempo surges "just to make sure the legs are there" is not.
Published training research is clear: fitness gained more than two weeks out is already baked in. Fatigue added in the final three days is not. Rest wins.
8. Changing your sleep schedule the night before
Trying to force 10 hours of sleep on Saturday night is a classic mistake. The anxiety of lying awake usually ruins it anyway.
What actually matters is the night before the night before.
Friday night is the sleep that fuels race day. Aim for a normal 7 to 8 hours Friday, and treat Saturday as a bonus if it comes.
9. Reading race-day advice from strangers on social media
Someone on Reddit will tell you to try beetroot shots. Someone on TikTok will swear by a 10-minute ice bath Saturday night.
None of these people have trained with you.
Trust the plan that got you to the start line. For more on this, see our guide to 10 things every runner should do the day before the race.
A 72-Hour Checklist That Actually Works
Three days out (Thursday)
- Short, easy 20 to 30 minute jog with 4 strides.
- Pick up bib and gear bag efficiently at the expo. Leave within 45 minutes.
- Lay out full race kit. Nothing new.
Two days out (Friday)
- Full rest or a 15-minute walk.
- Carb-heavy lunch and dinner from familiar foods.
- Aim for a strong 8 hours of sleep. This night matters more than Saturday.
One day out (Saturday)
- Light 10 to 20 minute jog, 2 strides, then stop.
- Hydrate steadily, not aggressively.
- Pack everything by 6 pm. Phone off social media by 9 pm.
The Race Begins Thursday
The Chicago Marathon starts in Grant Park at 7:30 am Central on Sunday, October 11, 2026.
But the race really begins the moment you walk into the expo.
Treat the next 72 hours like the final taper block, not a victory lap. For a deeper look at pacing the race itself, see our breakdown of 4 essential steps to get race-ready for your next marathon.
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