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Hydration Measurement Methods for Athletes

Cristina Vulpe provides three user friendly ways to check your level of hydration.

It is common knowledge that daily fluid intake has a significant impact on any athlete's training success. Whether this piece of information has been shared by a coach or not, the fact of the matter is that the amount of water and other fluids consumed in a day can vary largely from one type of sports person to the next. Besides, it can be influenced by the individual's age, gender, health status, and a variety of other factors.

Given that not all athletes have means of testing their hydration levels, it is a good idea to consider several simple hydration testing methods that can be performed both conveniently and efficiently.

Urine specific gravity

While it is likely to be the most sophisticated method of all, analyzing urine specific gravity is by far the most accurate way of measuring hydration. It requires the use of a refractometer. While the broad array of scientific gear destined for urinalysis calls for a set of skills or knowledge on the part of the user which athletes might not possess, the fact of the matter is that utilizing a refractometer is not all that difficult.

A simple handheld version can measure urine density in a matter of several minutes, thus letting sports people know whether they should drink more fluids or not. The athlete can collect his or her urine, calibrate the refractometer with the help of distilled water, and perform the urinalysis. Results range from 1.000 to 1.035, with the second number signalling severe dehydration.

The core advantage of this method is that it is easy to perform, even by athletes who have no prior experience with using a refractometer. Both the cost of the equipment and the fact that the urine has to be collected by the actual user could be drawbacks.

Nonetheless, using a refractometer is beneficial both for coaches and for athletes as a standard practice among professional and amateur boxers is to perform weight-manipulating techniques that involve dehydration [1]. When performed correctly, this method offers accurate results, although there have been cases where the consumption of certain medicines and vitamins have influenced the readings. Calibration of the refractometer is necessary before testing.

Urine colour

Another method of testing hydration involves assessing the athlete's urine colour. In order to perform this test, the urine has to be collected and tested first thing in the morning or can be stored for a time span of several hours. It should be noted that collecting samples both before and after a training session is a beneficial practice as it can underline the effect of the exercise on the sports person's hydration status.

Unlike the measurement involving the use of a refractometer, assessing the colour of the collected urine is far easier and can be done by any athlete, regardless of his or her background or technical expertise. However, it does require the use of a colour rating chart whose scale might vary depending on the publication that has made it available [2] [3].

There is practically no cost involved in performing this method as such a chart can be downloaded and printed from the internet for free. The test can be done either on the spot or by using samples that have been preserved in a refrigerator. As for the accuracy of the technique, it is worth mentioning that there have been medicines and vitamins which have affected the correctness of the results over time. In addition to this, consuming certain vegetables such as carrots and fruits such as blackberries might modify the colour of the urine. Fava beans, rhubarb, asparagus, and beetroot can also influence the findings.

Athletes interested in measuring their hydration levels using this technique are advised to avoid using a chart displayed on a computer or laptop screen as there may be differences compared in terms of colour correctness.

Sweat analysis

For the purpose of improving hydration practices, sweat patches can be applied to the athlete's skin in order to determine whether his or her hydration levels are on par. There are two kinds of patches available nowadays. Some are disposable, and others can be used time and again. Recently, several companies have come up with a design that enables users to connect sweat monitors to a mobile app and analyze the results using their smartphones.

Instead of measuring the amount of fluid in the urine as a refractometer or the formerly mentioned colour analysis would, such patches measure the electrolyte content of the athlete's sweat. Some of the common electrolyte levels that can be revealed with a sweat patch are sodium, magnesium, and potassium. Given that muscle cramping has been connected to low sodium, it is crucial for an athlete training for a competition to be aware of such figures in order to make the necessary adjustments to his or her dietary habits.

Sweat analysis can be performed by laboratories in the event that the use of such a patch is impossible. In situations like this, the sweat has to be collected and shipped to the laboratory for further analysis.

This method should be chosen by people who are known to eliminate a higher amount of sodium during exercise in comparison to others. The technique can assist them in defining their nutritional requirements so as to replace any sodium deficits. In order to avoid the negative effects of hypohydration on performance and health alike, fluid supplementation is required [4].

Furthermore, it has been suggested that certain exercises and fitness routines can lead to sodium depletion in a more timely fashion compared to others, which is why they should be either avoided or practiced after the athlete has hydrated using sports drinks.

As for the reliability of these patches, it is still a matter of debate. On the one hand, the results vary mainly due to the area where the patches are placed; they need to be set in sites such as the athlete's forehead, chest, or forearm, where the body perspires more heavily compared to other areas. The results have to be correlated with the intensity of the exercise, its duration, as well as the type of clothing worn by the user.

When it comes to ease of use, the version that seems to be most user-friendly is represented by the sweat monitor. It allows owners to utilize the product time and again and it transmits the results to a mobile app via Bluetooth or Wireless. Some traditional sweat patches still have to be placed in a centrifuge in order for the sweat to be collected and only then analyzed. The use of such equipment limits athletes greatly, as such gear might not be readily available for them. Furthermore, sending the perspiration sample to a laboratory for further analysis might prove to be less cost-effective. This last method may be better suited for research purposes.

The development of wearable multi-sensing patches for continuous sweat monitoring [5] could solve some of these user-related issues in that they could measure both electrolytes and metabolites and transmit the levels they have detected wirelessly so that the data is collected and stored with ease.

Conclusion

Even though two other methods can be used to test hydration, meaning sweat loss and sweat rate measurement, they are less preferred by actual sports people. The first involves measuring the body weight of the athlete, which is why the accuracy of the results is lower when compared to the techniques described above. The sweat rate can be measured only in certain parts of the body, which is why the patches have to be placed accurately and might fail to assess the loss of electrolytes in an efficient manner.

Measuring urine specific gravity, urine colour, and performing a sweat analysis can all be done fairly easy by sports people, therefore allowing them to avoid using the expensive services of a laboratory. Furthermore, such tests can be done alone or with the assistance of a coach, which means that they are, above all, convenient.

The cost of portable refractometers can vary from just under thirty dollars to a couple of hundred dollars, but auto refractometers used for research and scientific purposes can cost as much as four thousand.

Printing a urine colour chart costs little to nothing, so in this sense, it is the most cost-effective method of measuring hydration. Smart patches like Kenzen's ECHO are still in development, which is why it is difficult to tell just how economical or unreasonably priced they might be.


References

  1. ZUBAC, D. et al. (2016) Hydration status assessment among elite youth amateur boxers. J Sports Med Phys Fitness, 56 (6), p. 731-6
  2. ARMSTRONG, L.E. et al. (1998) Urinary indices during dehydration, exercise, and rehydration. Int J Sport Nutr., 8 (4), p. 345-55
  3. ARMSTRONG, L.E. et al. (1994) Urinary indices of hydration status. Int J Sport Nutr., 4 (3), p. 265-79
  4. REHRER, N.J. et al. (1994) The maintenance of fluid balance during exercise. Int J Sports Med, 15 (3), p. 122-125
  5. ANASTASOVA, S. et al. (2017) A wearable multisensing patch for continuous sweat monitoring. Biosens Bioelectron, 15 (93), p. 139-145

Page Reference

If you quote information from this page in your work then the reference for this page is:

  • VULPE, C. (2017) Hydration Measurement Methods for Athletes [WWW] Available from: https://www.brianmac.co.uk/articles/article249.htm [Accessed

About the Author

With a Ph.D. in veterinary oncology, Cristina Vulpe loves helping amateurs to better understand the daunting terminology depicting current gear and equipment employed for scientific purposes. As an avid reader and a tech aficionado, she spends most of her spare moments in the company of a good book or while checking on the latest advances of various scientific domains.

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