Hydration / Sodium / Endurance Fueling
A simple weigh-before/weigh-after method for estimating sweat rate. This guide is written for cyclists first, with notes that also apply to runners and triathletes when the same endurance-fueling principles carry over.
Good fueling is not about chasing a perfect number for its own sake. The goal is to deliver enough carbohydrate, fluid, and sodium for the session you are actually doing, using products and foods you can tolerate when the effort gets real.
Start with conditions, not a fixed rule
- Weigh before and after a representative workout.
- Account for fluid consumed and bathroom stops as best you can.
- Convert the difference into approximate fluid loss per hour.
Do not separate fuel from hydration
Carbohydrate, water, and sodium solve different problems, but they interact during real rides. A carb-heavy bottle might help energy intake, while plain water or electrolyte drink may be needed for thirst and fluid replacement. Sweat rate, weather, indoor cooling, and refill access all change the plan.
Where BonkGuard fits in
BonkGuard helps turn the planning pieces into a fueling timeline. You set the duration and target carbs per hour, choose the fuels for the plan, and use timing settings to create a schedule you can follow. The app also supports a Fuel Library, saved plans, in-ride reminders, and PDF exports including a compact stem card.
That makes BonkGuard most useful when you already have a realistic target and want to reduce mid-ride guesswork: what to take, when to take it, and whether the whole session adds up.
Useful next reads
- Beginner’s Guide to Cycling Nutrition
- Advanced Guide to Cycling Fueling
- How to Avoid Bonking on Long Bike Rides
- Cycling Fueling Calculator: What Inputs Actually Matter?
- Indoor Cycling Fueling: What Changes on the Trainer?
- See BonkGuard features
Key takeaway
Weigh before and after a representative workout. Build the plan around the full session, then keep the execution simple enough to follow when the ride gets hard.
Educational note
This article is educational and is not medical or nutrition-treatment advice. Athletes vary widely in tolerance, sweat rate, health history, and goals. Practice fueling and hydration changes in training, not for the first time on race day, and work with a qualified professional when you need individualized medical or nutrition guidance.