Dehydration in Tactical Athletes

Nov 20, 2020
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I spent part of last week in the field conducting hydration training for soldiers competing for the coveted EIB (expert infantry badge) and ESB (expert soldier badge). In the "absence" of war and deployments the EIB or ESB could very well become the deciding factor when it comes to career progression. Not something to be taken lightly. The Army EIB/ESB typically includes a two week train up and then a full week of testing including a physical fitness test.
Many times soldiers show up for training and testing in a dehydrated state. Dehydration can range from mild to severe and have serious performance consequences for individuals who need to perform their best. As little as a 2% drop in weight due to fluid losses can lead to physical and mental decrements. 2% of losses may not seem like much, but consider the 175lb athlete. A 2% loss is just 3.5lbs!
Consequences of Dehydration:
  • increased cardiovascular stress
  • difficulty regulating body temperature
  • increased fatigue and decreased endurance
  • reduced motivation due to increased perceived effort
  • decreased accuracy
  • reduced speed of complex tasks
  • reduced judgment distance
  • decreased concentration
  • decreased alertness
  • short-term memory difficulties.
The tactical athlete must be able to perform these tasks proficiently on a regular basis; Inability to do so when needed can indeed be the difference between life and death. Unfortunately many tactical athletes don't take their hydration seriously enough. In many instances hydration should be considered just as important as nutrition if not even more important. You can survive for up to two weeks without food but go without water for a couple of days and you're toast. Now consider the athlete who not only has to work in hot temperatures but also has to wear body armor and carry gear. Full battle dress with body armor can add about 5 degrees Fahrenheit to the ambient temperature.
Hydration can also be difficult for those tactical athletes that work primarily on the go or from their vehicles. For individuals such as firefighters the risk of dehydration is also high. Even though firefighters spend less than 10% of their time on average on fire ground almost half of firefighter injuries occur during this time. A 200lb firefighter could lose as much as 2% of their body weight in less than an hour while actively fighting a fire. If that firefighter is already dehydrated then losses that occur while working or even more detrimental. Dehydration has been shown to decrease strength by as much as 16%, which could be a major factor for injury.
Barriers to hydration:
  • lack of access to fluids
  • lack of food intake
  • insufficient time to drink
  • insufficient time / access to toilets
  • overuse of non-water fluids
So how can you determine if you're hydrated enough and how can you prevent dehydration?
While there's no universal definition of dehydration there are some different methods that you can use to ensure that you are getting enough fluids and electrolytes if needed to perform well. The most field expedient and less invasive way too in check if you are hydrated is to consider the color of your urine first thing in the morning. If you are well hydrated from the last 24 hour period then your urine should be a pale yellow. If it's looking more like you just poured a dark ale into the toilet chances are that you need to work on your hydration habits. Consider how much water have you drank in the last 24 hours. The old definition of 8 by 8 glasses of water in a 24 hour definitely does not work here. In reality the idea that you should drink 8 glasses of water a day comes from a misinterpreted paper from 1945, and has since the minimum standard has been updated.
In reality the idea that you should drink 8 glasses of water a day comes from a misinterpreted paper from 1945, and has since the minimum standard has been updated.

As little as a 2% drop in weight due to fluid losses can lead to physical and mental decrements.

To determine fluid losses, you can also check your weight before and after training or physical exercise. This can also give you some insight into how much water you will need for different training conditions:
Sweat loss = pre-exercise bodyweight - post-exercise body eight + (fluid intake - urine loss)
sweat rate = sweat loss / hours of training
Urine specific gravity (USG) can also be used to determine the extent of dehydration. USG can be checked in the field by a qualified individual such as a sports dietitian to assess urine concentration. A USG reading above 1.02 could indicate mild dehydration. A reading above 1.03 would indicate severe dehydration. In the event of severe dehydration, rehydration supplements should be used.
And of course, look at the color of your urine.
Try to drink fluids and water ad libitum (freely) throughout the day. Aim for non-sugar sweetened beverages to avoid unnecessary calories, which can contribute to weight gain. Water is still your best bet.
Some other tips to stay hydrated:
  1. Keep water within arms reach at all times.
  2. Occasionally use non-sugar sweetened flavoring to fight taste boredom and increase palatability
  3. Create a schedule of drinking and voiding if time or access is a barrier (ie 32 ounces 2 hours before a shift with a void just prior to shift, 32 ounces 2 hours before lunch with a void during lunch, and 32 ounces 2 hours prior to end of shift, with 16 ounces 1-2 hours before bed.) It will take practice to find what works for you.
  4. Use salt and electrolytes to increase thirst and help with retaining water if needed.
  5. Consume foods with a high water content such as melons and citrus.
And of course, always work with a professional when trying to determine your needs!
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  • McEVOY, M., & DRHODES, D. (2015). Hydration and Firefighter Performance. Fire Engineering, 168(4), 48–54.
  • Rogers, R., & Cole, R. (2016). Hydration Status in US Military Officer Students. U.S. Army Medical Department Journal, 24–29.
  • Zak, T. K., Hylden, C. M., & Johnson, A. E. (2018). Hydration Strategies for the Female Tactical Athlete. U.S. Army Medical Department Journal, 83–90.



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