Race Pacing & Fueling Strategy Planner
Upload your course GPX and set a goal. Get an elevation-aware, even-effort pacing plan — uphill splits slower, downhill faster — alongside a carbohydrate, fluid, and sodium timeline mapped to where you’ll be on the course. Free, no signup, runs entirely in your browser.
Pacing. The plan distributes a single, constant effort across the course rather than a constant pace. Each segment’s gradient is converted into a metabolic-cost multiplier using the Minetti cost-of-running polynomial, so climbs are paced slower and descents faster by exactly the amount that keeps energy expenditure even.1 Your goal time is met by solving for the one flat-ground pace whose grade-weighted total equals it. Where the course sits at altitude, a hypoxia factor (Wehrlin & Hallén) is applied from the GPX elevation itself.4
Carbohydrate. Targets follow Jeukendrup’s duration bands: ~30 g/hr for efforts under an hour, ~60 g/hr from one to about two-and-a-half hours, and up to ~90 g/hr (using multiple-transportable glucose:fructose mixes) for longer races, where the gut can absorb more than glucose alone allows.2
Fluid & sodium. If you enter a measured sweat rate, it is used directly. Otherwise fluid is estimated from temperature across the ACSM range of roughly 0.4–0.8 L/hr, and sodium from ~300–800 mg per litre of fluid — both clearly flagged as estimates, because real sweat and sodium losses vary widely between runners.3
- 1Minetti AE, Moia C, Roi GS, Susta D, Ferretti G. Energy cost of walking and running at extreme uphill and downhill slopes. J Appl Physiol. 2002;93(3):1039–1046.
- 2Jeukendrup AE. A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Med. 2014;44(Suppl 1):S25–S33.
- 3Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine Position Stand: Nutrition and Athletic Performance. Med Sci Sports Exerc. 2016;48(3):543–568.
- 4Wehrlin JP, Hallén J. Linear decrease in VO₂max and performance with increasing altitude in endurance athletes. Eur J Appl Physiol. 2006;96(4):404–412.
Every number here is a population average. The Minetti cost curve is fitted to a treadmill study; the carbohydrate bands assume a trained, fuel-adapted gut; and without a measured sweat rate, hydration is a guess that can be off by a factor of two. Net elevation also hides terrain — a course that rolls but nets to flat is paced very differently from a true flat.
The plan also can’t see the things that actually decide your race: how fatigue changes your economy late, how much carbohydrate your gut tolerates at intensity, how you handle heat, or whether your goal is realistic for your current fitness.
Vertical learns your personal terrain response, fueling tolerance, and sweat rate from your own GPS and heart-rate history, then builds race execution into the training that leads up to it — so race day runs the plan you’ve already rehearsed, not a textbook average.
Start free →Not sure of a realistic goal time? Race Time Predictor → · Adjust a result for heat, altitude, and grade with the Performance Calculator →