4.9 KiB
Race Logistics — fueling reference & plans
Reference doc: nutrition science, product cheat-sheet, race plans, watch setup. Personal findings/cues stay in NatesNotes.md.
Carb science in five bullets
- The gut absorbs glucose and fructose through separate transporters: SGLT1 (glucose) saturates around ~60 g/h; GLUT5 (fructose) adds another ~30–50 g/h on top. That's the entire reason dual-source fueling exists.
- Maltodextrin and dextrose are pure glucose for this purpose; sucrose is half glucose, half fructose.
- Targets by effort: >2.5 h → 60–90 g/h; the current elite trend is 90–120 g/h at ~1:0.8 glucose:fructose (Maurten/SiS Beta/Nduranz-style products) — measurably less fatigue in trail-marathon studies, but only with a trained gut. Build in long runs, never debut on race day.
- Hydration 450–750 ml/h (up to ~1 L/h hot). Sodium ~500–700 mg/h typical; true range is individual (200–1,500). Most "gel" GI distress is actually dehydration/sodium imbalance concentrating sugars in the gut.
- Pre-race: 100–150 g familiar carbs 2.5–3 h out. Start fueling at min 25–30. Post: 80–100 g carbs + protein within the hour.
Product reference (what's in the cabinet)
| Product | Per unit | Carb sources | ~glu:fru |
|---|---|---|---|
| Tailwind Endurance Fuel | 25 g carb, ~310 mg sodium / scoop | dextrose + cane sugar (sucrose) | ~3–4 : 1 |
| Hammer Gel | ~21–25 g carb / serving | ~80% maltodextrin + ~20% fructose | ~4 : 1 |
| Endurolytes Extreme | ~300 mg salt ≈ ~120 mg sodium, 75 mg K / cap | — | — |
Both fuels are glucose-dominant. Stacked at ~78 g/h that's ~60–63 g/h glucose — right at the SGLT1 ceiling, fine. Pushing this stack to 90+ g/h overloads the glucose pathway (GI risk) because the fructose share is too small; going higher means more Tailwind relative to gels or a 1:0.8 product for the 50K/50M.
Fructose sources (for raising the ratio past ~85 g/h)
- 1:0.8 products: Maurten 320, SiS Beta Fuel, Nduranz, Precision Fuel.
- Cheap: table sugar (sucrose = 50% fructose) in a bottle; DIY maltodextrin + crystalline fructose at ~1:0.8 + pinch of salt.
- Real food / aid station: honey (~40% fru), maple syrup, gummy candy, flat Coke (~55% fru), dates/raisins/figs (test fiber tolerance), bananas.
- Avoid as primary: agave (~85% fructose), apple juice — fructose solo absorbs slower and causes its own GI trouble; it only works as the co-fuel.
30K plan — 2026-06-13 (assumes ~4 h)
Targets: 75–80 g carb/h · 500–750 ml fluid/h · ~500–700 mg sodium/h
- Bladder: 6 scoops Tailwind in 2 L → 150 g carb, ~1,860 mg sodium. ~500 ml/h = 37 g carb + 465 mg sodium per hour; lasts exactly 4 h.
- 2 Hammer gels/h (on :00 and :30) = +40 g → ≈78 g/h total. Strong + stomach solid after hour 1 → 3rd gel in hours 2–3. Struggling → skip a gel, keep sipping. Never go to zero carbs.
- Endurolytes: carry 4; 1/h from hour 2 only if hot / salty sweater / cramp twinges. Tailwind covers baseline sodium.
- Carry: 8 gels + 2 spare · mixed bladder · 4 caps · 2 spare scoops in a baggie for refill points.
- Pre: 120–150 g carbs 2.5–3 h before · ~500 ml in the last hour · 1 gel 10 min pre-gun.
FR255 fueling reminders
Native (race-day choice): Run profile → hold UP → Run Settings → Alerts → Add New → Time → Recurring → 0:15. Mapping: every buzz = sip · every 2nd (:30s) = gel · every 4th (hourly) = salt check. Connect IQ alternative for labeled eat/drink intervals: Eat! Drink! Reminder! — test on a training run first; costs a data-field slot.
Before the 50K (2026-07-25)
- Gut-train toward 90 g/h on long runs (raise Tailwind share, or trial a 1:0.8 glucose:fructose fuel).
- Re-derive sodium needs from how the 30K went (cramps? salt crust? nausea?).
- Log the 30K outcome below.
Race log
- 2026-06-13 30K — (fill in: finish time, what was consumed, GI notes, cramps, what to change)
Sources
120 vs 90 vs 60 g/h trail marathon · CHO & GI problems in ultra-trail review · Cadence ultramarathon guide · Precision Hydration ultra fueling · Tailwind nutrition · Hammer Gel · Endurolytes Extreme · FR255 alerts manual