Cardio
Sweat-Rate + Electrolyte Marathon Plan
Compute marathon sweat rate and a personalized fluid + sodium intake plan from a single training session.
Result
Sweat versus the drinking plan
Per hour of racing.
Hydration plan
- Before: 400 mL at least 4 hours before the start.
- During: 460 mL an hour with 529 mg sodium.
- After: 2,250 mL over the following hours (1.5 L per kg still lost).
Related calculators
- Nutrition TDEE Calculator
Estimate your daily energy expenditure with Mifflin-St Jeor + activity factors.
- Nutrition Macro Calculator
Convert calorie targets into protein, carbs, and fat grams for your goal.
- Planning Calorie Deficit Calculator
Estimate required daily calorie deficit for a target timeline and bodyweight change.
- Planning Body Recomposition Planner
Plan body-fat reduction pace, deficit targets, and protein needs around a timeline.
Articles
- 10 min read Heat Acclimatization: Sodium and Plasma Volume
Heat acclimatization shifts plasma volume up 10-12% in 10-14 days. The sodium math that supports the adaptation and the workouts that drive it.
- 7 min read Marathon Sweat Rate: 70kg Runner, 2% Body Mass Loss in Warm Conditions
Marathon sweat rate 0.57 L/h, total loss 2.3 L over a 4-hour temperate race. Body mass loss 2.1%, 460 ml/h fluid plan, 529 mg/h sodium target.
- 11 min read Heart-Rate Zones: Methods Compared
Heart-rate zone methods compared: Karvonen, %HRmax, %HRR, lactate threshold — accuracy by training age, error bands, and which one for which goal.
Use it from an agent or code
Any agent can run this calculator by URL: put the inputs in the query string and get JSON back, with the inputs that used defaults and a line to cite (add format=md for markdown). MCP clients reach it through https://aifithub.io/mcp.
In code, import the same module; it runs where you import it, with no request or key.
import { compute } from "https://aifithub.io/engines/sweat-rate-electrolyte-marathon.js";Input and output contract, TypeScript types and the guide for agents.