Recent News and Events

by Cuyler Hudson, DPT

Posted in Team Finish Line.

August 6th, 2018

How to Develop an Individualized Hydration Plan

You’ve all heard it before, “drink eight glasses of water a day in order to stay hydrated.” However, if you take one look at the different sizes and shapes of people around you, it seems pretty crazy to assume everybody needs the same amount of water. It turns out that the study that led to the eight 8 oz glasses of water a day recommendation was very poor science.


Hydration level IS extremely important, especially to endurance athletes such as runners and triathletes. But a host of factors including size, workout routine, sweat volume, and diet all influence how much water you need. We know that poor hydration leads to poor performance.  While this is less so with short-bouts of exercise, for distance athletes, studies have demonstrated anywhere from a 7 to 60% reduction in performance with as little as 2% deficit of body water content (1). We also see an increase in musculoskeletal injury rates as dehydration increases (2).


There are two main factors you have to think about when addressing your hydration needs. Firstly, resting hydration level. This is your hydration status at the beginning of the day. Secondly, post-exercise hydration level, meaning how much water you lose during exercise. It is important to also note that it is indeed possible to over-hydrate. (A former teammate of mine once ended up in the hospital with full body cramps after over-hydrating for a football game he didn’t get playing time in). Most professional athletic organizations will check the urine osmolality of each athlete every single day in order to determine hydration. However, the prospect of urinating into a little machine every morning can be very unappealing to the casual athlete. So the question is asked, how do you stay on top of your hydration without expensive machines or urine samples?


The best way to easily monitor resting hydration status for a casual athlete is by urine color. Urine color is determined by a metabolite called urochrome, which is naturally a brownish color. The more water you expel, the more this urochrome is diluted, and the lighter the color will be (2). When monitoring urine color, it is important to be consistent in the time of day you take note. Checking first thing in the morning, when most factors will be consistent day to day, is best. What you want to see is a very light color, bordering on clear. You can increase your amount of daily water intake (make sure to keep note of how much you consume), until you consistently see this color every morning. This should be your new goal each day for water consumption.


The second part of the hydration equation is water consumption during/post exercise. The best thing to do is to weigh yourself before and after each workout as you are figuring out how much you need to drink. Since we are only losing weight through our sweat and respiration, we know each pound lost during exercise is from water. You should never exceed more than 2% of your body weight lost during exercise. If so, you need to drink more during/directly after exercise. Also, you shoulder never gain weight after an exercise. If so, you are drinking too much water and are at risk for overhydration (2).


Finally, in addition to water, we also lose a LOT of a key electrolyte, sodium during exercise (which is why our sweat is salty). While we do tend to get enough sodium through our diet for non-workout days, it is beneficial to put a teaspoon of salt in the water you consume if you are planning a heavy workout for the day (3). While the research remains a little muddy on the exact cause, (more to come on how neuromuscular fatigue may be affecting your exercise) maintaining adequate electrolyte levels may help prevent you from dreaded cramps!


Try this out, and you may start to notice differences in how you feel, how you perform, and you might just save yourself from an injury!



  1. Judelson, D. A., Maresh, C. M., Anderson, J. M., Armstrong, L. E., Casa, D. J., Kraemer, W. J., & Volek, J. S. (2007). Hydration and muscular performance. Sports Medicine37(10), 907-921.
  2. Maughan, R. J., & Shirreffs, S. M. (2010). Development of hydration strategies to optimize performance for athletes in high‐intensity sports and in sports with repeated intense efforts. Scandinavian journal of medicine & science in sports20, 59-69.
  3. Williams, J., Brown, V. T., Malliaras, P., Perry, M., & Kipps, C. (2012). Hydration strategies of runners in the London Marathon. Clinical Journal of Sport Medicine22(2), 152-156.


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