Hydration Monitoring: Top Methods Used By The Pros
Updated: May 2
When it comes to health and performance, optimal hydration plays a central role of keeping athletes in the game. Decreases in fluid level leading to a dehydrated state impacts performance in sport, where even losses of up to 2% of an athlete’s body mass can reduce work outputs and endurance. It’s not just endurance that is impacted either, as strength and power losses of up to 5 to 6% can occur at the same status of dehydration. Imagine the circumstance where an athlete is showing up even slightly dehydrated on a daily basis, and each day they are missing their fullest potential because of it. How much faster, stronger, fitter, or better could they have been over time if hydration hadn’t fallen through the cracks? Needless to say, showing up well hydrated to practice, training or competition in any athletic event is a minimum standard all athletes should abide by.
Hydration status can be monitored in several ways by both athletes as well as health and performance staff members. While laboratory-based testing using blood or urine samples is considered to be of higher quality, they have traditionally been the most difficult to implement in a team setting. Because of this many athletes and teams opt to use easier testing methods, despite limitations of accuracy or reliability. These methods include subjective urine color charts, weigh-ins and sweat rate, and relative thirst levels.
Given the importance of hydration and fueling, as well as the unique challenges that come along with the variety of options, what exactly are athletes and teams doing behind the scenes to keep tabs on hydration?
Method: Weigh-ins (Pre- and Post-Activity)
PROS: weighing in pre- and post-activity offers a very good indicator of sweat loss and hydration status, and this can be done daily throughout the week. When paired with sweat rate that also takes into consideration fluid intake and urine loss, athletes can take action on hydration amounts over time for replenishment
CONS: pre- and post-activity weigh-ins can be highly variable and aren’t always the most repeatable and reliable due to clothing and timing. Sweat rate can also be highly individual, and this method also requires the collection and handling of urine and bodily fluids which is messy and time consuming.
Method: Blood/Plasma Osmolality
PROS: considered to be the closest to a “Gold Standard” within hydration assessment and are utilized in medical and research settings. These are considered a close proxy to hydration status as osmolality testing focuses on determining the concentration of a solution such as plasma or urine.
CONS: it isn’t hard to imagine that drawing blood from an athlete is incredibly invasive, sometimes quite painful, and is certainly not something that most all athletes want to do on any type of regular basis. This is a method that is performed least often and has the least amount of repeatability in a team setting as well.
PROS: can be intertwined with pre- and post-activity weigh-ins and provides insight into total body water volume. This can be done on a near daily basis and performed throughout the day as well.
CONS: the equipment can be very expensive and require dedicated space and access that can be difficult to accommodate. Bio-Impedance also possesses a (relatively) high error variance for assessing total body water, even when adhering to strict protocols. As many athletes and staff know, it can be quite difficult to adhere to strict measurement protocols in a busy team setting.
Method: Saliva Testing and Thirst Assessment
PROS: osmolality of saliva appears to correlate well with hydration status and can be administered on a near daily basis via a minimally invasive process. Saliva testing can sometimes be used as a proxy for subjective thirst levels, which is obviously an easily implemented method.
CONS: saliva testing requires daily collection of bodily fluids for assessment, which demands safety/protective health equipment for handling and disposal. Additionally, the timing of the saliva testing and any hydration intake such as a 10 second mouth rinse with water can significantly skew results and give a false indicator of hydration. As many already know, the subjective nature of thirst levels may be considered a “too little too late” approach for assessing hydration given the latency in onset of thirst.
PROS: an easily administered assessment for athletes to use each time they urinate during the day, every day. Urine color charts posted within restroom facilities offer guidance to athletes when visually assessing the color of their urine. Darker urine may indicate higher levels of dehydration, and pale colored urine may indicate more appropriate levels of hydration.
CONS: assessing urine color is highly subjective and can be influenced by athlete bias, lighting within the restroom itself, as well as by the quality of the corresponding colors on urine charts. There can also be great uncertainty about the impact of the color interpretation by the athlete and to the level of hydration status the urine color actually corresponds with.
Method: Urine Specific Gravity (USG)
PROS: process that uses a simple testing apparatus that measures the density of urine relative to water. The procedure is non-invasive to the athlete and gives objective criteria for health and performance staff to assess hydration status that can be correlated or compared to laboratory grade osmolality testing. USG itself has become a widely known metric that many athletes and teams use 1-2 times per week in relationship to competition or game days.
CONS: the timing of the USG testing process can impact test results, and in many cases the athletes never see the information in a timely matter. Using traditional USG methods such as a refractometer requires handling and disposal of urine samples, and also requires the athlete to handle their own urine samples. Compliance with USG testing can be difficult because of this.
What Is The Best Way To Monitor Hydration?
There are reoccurring themes when assessing the pro’s and con’s of each method:
First, invasive methods are not preferable by athletes or staff alike.
Second, accuracy and reliability of hydration status must take priority as well.
Third, handling and disposal of bodily fluids when monitoring hydration is messy and time consuming.
And lastly, hydration monitoring should be performed on a near daily basis due to it’s importance for athlete performance and health.
Given all of these parameters it seems as if athletes and teams have to either settle for enhanced accuracy and messy, invasive, time consuming testing or less accurate but frequent monitoring practices that leave hydration status up to interpretation and guess work.
It’s Time Hydration Monitoring Caught Up With The Times
Intake Health’s InFlow hydration monitoring solution combines laboratory grade testing seamlessly with an athlete’s daily routine giving the best-of-both-worlds for staffs wanting to maximize accuracy while minimizing messes and time wasting. Athletes can now get instant, objective feedback on their hydration status every day without added testing, without guesswork, all received in time for them to properly hydrate before they perform.
Want to learn more about continuous hydration monitoring without adding headaches for your staff or your athletes? Connect with one of our practitioners and learn how to evolve your team's approach to optimizing hydration and performance.