Sweat Rate & Sodium Loss Calculator - Hydration Science
Weigh in before and after exercise to calculate exact fluid replenishment and sodium intake needed to prevent dehydration and muscle cramps.
How to Use Sweat Rate & Sodium in 3 Simple Steps
Step 1: Upload
Drag & drop your .FIT, .GPX, or .TCX activity file. All processing is 100% private in your browser.
Step 2: Process
FitCrop inspects telemetry streams, removes anomalies, recalibrates metrics, or fixes binary checksums.
Step 3: Export
Download your clean Strava, Garmin, and Zwift compatible file with 1 click. Zero server wait.
Frequently Asked Questions
How do I calculate my sweat rate?
Weigh yourself naked immediately before and after exercise. Subtract post-weight from pre-weight, add fluid consumed, subtract urine output, and divide by workout hours.
How much sodium does an athlete lose in sweat?
Sweat sodium varies from 500 mg/L (mild sweaters) to over 1,800 mg/L (salty sweaters with white residue on kit). Matching 70-80% of lost sodium prevents hyponatremia and cramps.