Measurement of Sodium in Athletes’ Sweat  

LAQUAtwin is a series of pocket ION meters. Using Ion Selective Electrode (ISE) technology, they are available for measuring Conductivity, Calcium, Nitrate, Potassium, Sodium, Salt concentration and pH measurement. Using just a tiny amount of sample, the LAQUAtwin proprietary flat sensors can quickly and accurately measure the values of the chemical parameters in the field.


It is useful to determine the amount of sodium present in sweat as replacing sodium (Na+) lost from sweating plays an important role in preventing fluid and electrolyte imbalances. By finding the amount of sodium lost, one may estimate the amount of electrolyte that should be replaced.

Sweat can usually be tested for sodium content by a ion chromatography techniques in analytical laboratories. But most athletes do not have ready access to such facilities. The Horiba ion tester can be used instead of the traditional ion chromatography in order to determine the amount of sodium in sweat

The LAQUAtwin Na+ meter is used as simple test to determine  the Sodium ion content of sweat in order to replace the electrolytes after intense activity. This is an easy, quick method used to check the amount of sodium present in sweat.


When the subject has begun to sweat, the target sites must be cleaned with deionized water and dried. Then, sterile patches can be applied directly onto the right anterior mid-thigh, right posterior mid forearm, left posterior mid forearm, upper chest, right scapula, left scapula, and forehead. The subjects should then continue with their strenuous activity and the patches removed just before they are saturated with sweat.

Sweat is then extracted from the patches. A small sample of the sweat solution extracted is placed on the sensor of the LAQUAtwin Na+ and measured. To repeat sampling, wash the sensor with tap  water and pat dry with a paper tissue.

Results and Benefits

By using accurate Sodium ion testing for sweat in athletes, we can determine the electrolyte imbalance and thus athletes can better address this by optimising their electrolyte intake during activity.

Though ion chromatography is the gold laboratory standard, the results derived by Horiba’s ion analysis alternate method are not only simpler to acquire, but also accurate.

According to a study by Gatorade Sports Science Institute, ‘On the basis of typical error of the measurement results, sweat [Na+] and [K+] obtained with HORIBA falls within `15.4 mEq/L and `0.68 mEq/L, respectively 95% of the time’.

The LAQUAtwin Na+ pocket meter is small and compact; convenient to carry around the marketplace for easy on-site testing. Its easy-to-use interface is simple for anyone to use the LAQUATwin Na+ pocket meter.

Click on image to enlarge.


Lindsay B. Baker, Corey T. Ungaro, Kelly A. Barnes, Ryan P. Nuccio, Adam J. Reimel, and John R. Stofan “Validity and reliability of a field technique for sweat Na+ and K+ analysis during exercise in a hot-humid environment”  Physiological Reports Vol. 2 Issue 5 (2014)

Eric D. B. Goulet, Tommy Dion, and Étienne Myette-Côté “Validity and reliability of the Horiba C-1 compact sodium analyzer in sweat sample of athletes” European Journal of Applied Physiology (2012)

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