evidence-based endurance hydration planning
v1by FitnessGrid
Develop a personalized 8-week hydration training and race strategy based on measured sweat rates and fluid loss thresholds.
hydrationsweat-rateendurancerace-prep
Get an AI coach that uses this skill
FitnessGrid is an AI coach that plans your week and adapts as you go. Install evidence-based endurance hydration planning and your coach will follow this protocol every week, learn from what you actually do, and adjust on the fly.
- Your coach builds the week from this skill
- Adapts to your actual progress, not a static template
- Free to start — no credit card, ~60 seconds to set up
Procedure
-
Phase 1: Baseline Mapping (Weeks 1-2)
- Instruct the user to perform a 60–90 minute field-simulation test at race intensity.
- Record pre-exercise nude body weight and post-exercise nude body weight (after towel drying).
- Track fluid intake (mL/oz) and urine loss during the session.
- Calculate Sweat Rate (L/hr):
((Pre-Weight - Post-Weight) + Fluid Intake - Urine Loss) / Duration. - Calculate Fluid Loss Percentage:
((Pre-Weight - Post-Weight) / Pre-Weight) * 100. - Categorize sweat rate: Low (<0.5 L/hr), Low-to-Mod (0.5–1.5 L/hr), High (1.5–2.5 L/hr), or Very High (>2.5 L/hr).
-
Phase 2: Gut Training (Weeks 3-4)
- Design training sessions to gradually increase fluid intake during long efforts.
- Aim to identify the upper limit of gastric emptying before gastrointestinal (GI) distress occurs.
- Use
create_noteto log GI symptoms and fluid volumes successfully absorbed.
-
Phase 3: Tolerance Testing (Weeks 5-6)
- Schedule race-pace efforts where fluid intake is managed to allow a calculated 1–2% body mass loss.
- Monitor perceived exertion and performance metrics to ensure loss does not exceed 2%, where performance typically declines.
-
Phase 4: Race Simulation (Weeks 7-8)
- Finalize a "flexible prescription" based on the established sweat rate ceiling.
- Execute a full race-day simulation during the final long effort, incorporating both volume and personalized electrolytes.
-
Race Day Strategy Formulation
- Pre-Hydration: Recommend 500 mL of fluid 1–2 hours before the start.
- Intra-Race: Aim to replace a significant portion of hourly loss, ensuring total intake does not exceed 100% of sweat loss to avoid hyponatremia.
- Recovery: Recommend consuming 1.25 to 1.5 L of fluid for every 1 kg of body mass lost post-race to return to euhydration.
-
Documentation & Memory
- Use
rememberto store the user's specific sweat rate and sweat rate category. - Use
create_noteto provide the final personalized "Condition Matrix" for different temperatures (e.g., cool vs. hot race conditions).
- Use
