Estimated sweat loss during exercise
Sweat (L) ≈ pre-weight − post-weight (kg) + drink (L) − urine (L); rate = sweat / duration in hours. Weigh under matching conditions without wet clothing.
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Calculation
Result
- Sweat Rate
- 1.70 L/h
- Total Fluid Lost via Sweat
- 1700 mL
- Body mass loss during exercise
- 1.6 %
- Recommended Rehydration Volume
- 1200 – 1800 mL
Individual fluid loss pace under current temperature and intensity conditions
Percentage body mass loss does not diagnose dehydration; a negative value indicates gain. NATA (2017): 100–150% of net body mass loss is a conditional postexercise replacement reference, especially with recovery under four hours. It is not a mandatory amount for everyone or an intake rate during exercise.
Percentage body mass loss does not diagnose dehydration; a negative value indicates gain. NATA (2017): 100–150% of net body mass loss is a conditional postexercise replacement reference, especially with recovery under four hours. It is not a mandatory amount for everyone or an intake rate during exercise.
Percentage body mass loss does not diagnose dehydration; a negative value indicates gain. NATA (2017): 100–150% of net body mass loss is a conditional postexercise replacement reference, especially with recovery under four hours. It is not a mandatory amount for everyone or an intake rate during exercise.
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How it is calculated
Sweat (L) ≈ pre-weight − post-weight (kg) + drink (L) − urine (L); rate = sweat / duration in hours. Weigh under matching conditions without wet clothing.
Formula
Sweat (L) ≈ pre-weight − post-weight (kg) + drink (L) − urine (L); rate = sweat / duration in hours. Weigh under matching conditions without wet clothing.
Limits of the method
Percentage body mass loss does not diagnose dehydration; a negative value indicates gain. NATA (2017): 100–150% of net body mass loss is a conditional postexercise replacement reference, especially with recovery under four hours. It is not a mandatory amount for everyone or an intake rate during exercise.
Sources of the method
- NATA. Fluid Replacement for the Physically Active, 2017.
- American College of Sports Medicine et al. American College of Sports Medicine position stand. Exercise and fluid replacement. Med Sci Sports Exerc, 2007
- Thomas DT et al. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. J Acad Nutr Diet, 2016
- Shirreffs SM et al. Fluid and electrolyte needs for training, competition, and recovery. J Sports Sci, 2011
This calculation is for reference only and is not medical advice, a diagnosis or a prescription. If you have a medical condition, are pregnant, take medication or have any doubts, discuss the result with a physician or a qualified nutrition professional.
How to use the calculation
Enter the starting values
Sweat (L) ≈ pre-weight − post-weight (kg) + drink (L) − urine (L); rate = sweat / duration in hours. Weigh under matching conditions without wet clothing.
Adjust the parameters
Sweat Loss (mL) = (Pre_Weight − Post_Weight, g) + Fluid_Consumed(mL) − Urine(mL); Sweat Rate (L/h) = (Sweat Loss / Duration_min) × 60 / 1000; Dehydration % = ((Pre_Weight − Post_Weight) / Pre_Weight) × 100.
Read the result
Percentage body mass loss does not diagnose dehydration; a negative value indicates gain. NATA (2017): 100–150% of net body mass loss is a conditional postexercise replacement reference, especially with recovery under four hours. It is not a mandatory amount for everyone or an intake rate during exercise.
Frequently asked questions
What does the calculation show?
Sweat (L) ≈ pre-weight − post-weight (kg) + drink (L) − urine (L); rate = sweat / duration in hours. Weigh under matching conditions without wet clothing.
What limitations apply?
Percentage body mass loss does not diagnose dehydration; a negative value indicates gain. NATA (2017): 100–150% of net body mass loss is a conditional postexercise replacement reference, especially with recovery under four hours. It is not a mandatory amount for everyone or an intake rate during exercise.
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What next
Formula breakdowns, biomarker reference ranges and nutrition articles with cited sources are in the NutriFit knowledge base.
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