For more than 30 years, the Gatorade Sports Science Institute (GSSI) has worked with athletes—both on and off the field—to study every aspect of hydration. What has GSSI learned? That there is more to sweat than meets the eye.
Sodium is not “one size fits all”
The amount of sodium found in athletes’ sweat can vary drastically from one person to another. Sodium content in sweat ranges from 230 - 2,070 mg/L, which is approximately 1/25 to 1 full teaspoon.
Who, what & where you are affects sweat rate
Sweat losses can be affected by numerous factors including: the climate, heat acclimatization status, the sporting equipment worn, the exercise intensity, and duration.
Knowing an individual’s hydration needs during exercise enables athletes and coaches to maximize athletic performance and help minimize hydration-related risks and dehydration. An accurate way to assess an individual’s hydration needs is by calculating their sweat rate.
Visit GSSI to utilize the Fluid Loss Calculator
Note: Sweat rate should be measured multiple times throughout a season as it will vary with environmental conditions and level of competition.
Best practices for determining whole-body sweat rate
- Test in conditions (intensity, environment, season, equipment, etc.) relevant and specific to that of the athlete’s training/competition
- Have athletes wear minimal clothing for all body mass measures
- Weigh athletes in the same clothing before and after exercise
- Monitor and weigh all fluid/food intake and urine losses during exercise
- Barnes KA, Anderson ML, Stofan JR, Dalrymple KJ, Reimel AJ, Roberts TJ, Randell RK, Ungaro CT, Baker LB (2019). Normative data for sweating rate, sweat sodium concentration, and sweat sodium loss in athletes: an update and analysis by sport. J Sports Sci. Epub ahead of print.
- Laitano O, Runco JL, Baker L (2014). SSE #128: Hydration Science and Strategies in Football. 27:128. http://www.gssiweb.org/en/Article/sse-128-hydration-science-and-strategies-in-football.
- Baker LB, Barnes KA, Anderson ML, Passe DH, Stofan JR (2016). Normative data for regional sweat sodium concentration and whole-body sweating rate in athletes. J. Sports Sci. 34:4.
- Baker LB (2016). SSE #161: Sweat testing methodology in the field: challenges and best practices. 28:161. https://www.gssiweb.org/en/sports-science-exchange/Article/sse-161-sweat-testing-methodology-in-the-fieldchallenges-and-best-practices
- Baker LB, De Chavez PJD, Ungaro CT, Sopena BC, Nuccio RP, Reimel AJ, Barnes KA (2019). Exercise intensity effects on total sweat electrolyte losses and regional vs. whole-body sweat [Na+], [Cl-], and [K+]. Eur J Apply Physiol. 119(2):361-375.
- Baker LB, Ungaro CT, Sopena BC, Nuccio RP, Reimel AJ, Carter JM, Stofan JR, Barnes KA (2018). Body map of regional vs. whole body sweating rate and sweat electrolyte concentrations in men and women during moderate exercise-heat stress. J Appl Physiol. 124(5):1304-1318.
