The working
0.5-2.5+ L/hrTypical range
1 lb = 16 ozScale conversion
Replace 80-100%Training target
Aspire Hydration

Use pre- and post-workout weight to replace what the athlete actually loses.

A sweat-rate test turns hydration from a guess into a number the coach and athlete can use across training conditions.
  1. 1
    Every athlete leaks fluid at a different rateTwo athletes can train side by side and lose very different amounts.Heat, humidity, altitude, and intensity all change sweat rate.
  2. 2
    Use a controlled practice windowWeigh the athlete before practice in dry clothes or nude.Track every ounce of fluid consumed during the session.
  3. 3
    Calculate sweat rate from real dataWeight lost plus fluid consumed equals total sweat loss.Divide by session length to get hourly sweat rate.
  4. 4
    Build the replacement target from the testAim to replace 80-100% in training.Aim to replace 70-90% in races if full replacement is not realistic.
  5. 5
    Fix the easy mistakes firstDo not use wet clothes or a bathroom break without adjusting the math.Do not assume one test applies to every weather condition.
Aspire Performance & Nutrition: the sweat-rate test is the cleanest way to stop guessing and give each athlete a hydration target that matches the real session.
Aspire Performance & NutritionSources online