Why long runs are the real test
Knowing your target range (see carbs per hour running) only helps if your gut can actually handle it at the pace and duration you'll race at. Long runs are the only place to find that out before it matters.
What to practice
- The exact products you plan to race with. Same gels, same drink mix — not just "something similar."
- The timing you plan to use. If your race plan is a gel every 25 minutes, run a few long runs on that same schedule.
- Race pace, not just race distance. A gut that handles a gel at easy pace doesn't automatically handle it at race effort.
How often to rehearse
A few long runs at or near race pace, fueled exactly as planned, is generally enough to know whether a plan holds up. One good test beats zero, but repeating it a few times catches problems that don't show up the first time.
When something doesn't sit right
If a product causes trouble in training, that's useful information — better to find out now and swap it than discover it mid-race. Common fixes: a different format (chews instead of gel), a smaller more frequent dose, or plain water alongside it.
Building up gradually
If your race-day target is higher than what you currently tolerate, raise your training intake gradually over several weeks rather than jumping straight to the number. Gut tolerance for carbohydrate responds to practice the same way pacing and mileage do.
Common mistakes
- Only fueling "some" long runs. The ones closest to race distance and pace deserve a genuine rehearsal.
- Testing a brand-new product on race day. If it hasn't been in a long run, it doesn't belong on the course.
- Ignoring pace when practicing. Easy-pace tolerance and race-pace tolerance aren't the same thing.