The Deconstructed Dish: 3 Easy Ways to Avoid Overhydration When Working Out

By Jenn Randazzo, MS RD on August 11, 2015 , categorized in Endurance

Who has time to stay savvy about latest nutrition research these days? Besides, a nutritional breakthrough or wonder food makes headlines every Monday only to be disproved by Tuesday, right?  Even though you may be seconds away from tossing in the kitchen towel and just eating your favorite comfort foods because you’re so frustrated and confused, don’t yet.

Nutrition trends come and go, but I’m here to provide you with evidence-based, sustainable ways to improve your health.  Each month, I’ll focus on a nutritional hot topic, sift through tons of research, separate fact from fiction, and provide realistic solutions to help you improve your life.

We’ve all seen it.  Marathoners stumbling across the finish line. Soccer players lying on their backs and grabbing the back of their calf. Cyclists leaning over their bike’s handlebars complaining of weakness and dizziness.

After I think, “Geez I seriously hope they are OK” I am reminded of how tricky hydration can be. Because  properly hydrating isn’t that simple, especially for athletes. It requires an individual to know how to maintain the delicate balance between fluid (water) and electrolyte inputs (sodium, potassium, chloride and magnesium) with their outputs, which can be very challenging to measure.  Accurately recording consumption of fluids and electrolytes while documenting those lost by breathing, urinating and sweating is time consuming, cumbersome and, frankly, down-right a snoozefest.

However, there can be serious repercussions of not hydrating properly; namely, dehydration and overhydration.  And as much as I would like to discuss both, I feel dehydration is discussed and documented waaaaayyyyyyyyyy more than being “water drunk.”  So, you know what?  I’m going to give overhydration a little love today by discussing what it is, how it happens, and most importantly, how we can help prevent it. #nobodyputsoverhydrationinacorner

Overhydration, or water intoxication, occurs when your body retains more water than it needs.  Now, before you freak out, let me share that overhydration is fairly rare, especially for the general population, because of your body’s amazing ability to regulate its water balance.  However, for those engaged in endurance sporting events, like marathons, traiathalons, etc., overhdyration has become a more well-known risk. In an attempt to prevent dehydration, endurance athletes may unknowingly overhydrate. Individuals who consume copious amounts of water (like 2.5 to 5 gallons) within a short period of time severely dilute their body’s blood sodium concentration, increasing risk for hyponatremia1Whitney E and Rolfes S. (2013) Understanding Nutrition. Instructor’s Edition. Wadsworth Cengage Learning. 454. .

Sifting through the research

Hyponatremia 101

Most often resulting from overhydration, hyponatremia occurs when blood sodium concentration falls to an abnormally low level (<135 mmol/liter). Along with less severe symptoms like headaches and bloating, hyponatremia prompts a rapid and dangerous swelling of the brain that can result in seizures, coma, and death2 Nagler E et al (2014) Diagnosis and treatment of hyponatremia: a systematic review of clinical practice guidelines and consensus statements. BMC Medicine. 12:231. Accessed on 7/20/15 from

Symptoms of hyponatremia

The symptoms typically correlate with the severity of the deficiency.  Individuals with hyponatremia of <125-135 mmol/liter may experience some slight gastrointestinal disturbances, like gas, bloating and/or nausea.  Below 125 mmol/liter, the symptoms become more severe and include throbbing headache, vomiting, wheezy breathing, swollen hands and feet, restlessness, unusual fatigue, confusion, and disorientation3Adrogue H and Madias N. (2000) Hyponatremia. The New England Journal of Medicine. 342:1581-1589. . When plasma sodium concentration drops below 120 mmol/liter, seizure, respiratory arrest, coma, permanent brain damage, and death become more likely. However, some athletes have survived hyponatremia of <115 mmol/liter4Backer, et al. (1993). Hyponatremia in recreational hikers in Grand Canyon National Park. Wilderness & Environmental Medicine. 4(4):391-406.  whereas others have died at higher concentrations.

Causes of hyponatremia

If you look at potential causes of hyponatremia within the general population, you could end up with a longer list than you anticipated.  According to a review article conducted by researchers Adrogue and Madias, over 60 possible factors could contribute to the condition5Adrogue H and Madias N. (2000) Hyponatremia. The New England Journal of Medicine. 342:1581-1589..  However, for endurance athletes, the causes of hyponatremia are reduced significantly.  In fact, for otherwise healthy athletes, hyponatremia is typically caused by6 Casa, D. (2002) Proper Hydration for Distance Running Identifying Individual Fluid Needs. A USA Track & Field Advisory. Accessed on 6/25/15 from:

  1. Too much fluid in the body/overhydration
  2. Too little sodium in the body
  3. A combination of both

Too much fluid in the body/overhydration

While it is possible that hyponatremia in athletes can result from unusual electrolyte shifts, the more likely scenario is that athletes, in an attempt to prevent dehydration, overhydrate before and/or during endurance sporting events.  For example, researchers reported that 18% of the 330 race finishers at the 1997 New Zealand Ironman triathlon were hyponatremic, and of those, fluid/water overload was responsible for 73%7 Speedy DB, et al (1999). Hyponatremia in ultradistance triathletes. Medicine and Science in Sports Exercise. 31:809-815..

Too little sodium in the body

Now, this is where I found the research really interesting.  When researchers first began studying hyponatremia, they emphasized the importance of consuming adequate amounts of sodium.  However, over the past decade or so, the focus has shifted towards proper water consumption throughout the days prior to and of the event.  More and more researchers agree that overhydration is the main reason for hyponatremia8 Whitfield A. (2006). Too much of a good thing? The danger of water intoxication in endurance sports. British Journal of General Practice. 56(528):542-545. Accessed on 7/20/15 from:

Who’s at risk for hyponatremia?

Athletes at risk for developing hyponatremia are individuals who9Casa, D. (2002) Proper Hydration for Distance Running Identifying Individual Fluid Needs. A USA Track & Field Advisory. Accessed on 6/25/15 from:

  • Overhydrate (drink 2.5-5 gallons of water within a short period of time) before, during or after sport.
  • Lose a lot of sodium while sweating, and don’t replenish it at all during prolonged sporting events (>3 hours).

What to do if you think you’ve overhydrated

If you experience any of the various symptoms listed above during or after exercise, see a medical professional right away.  Like, get yourself to the hospital, stat.  Based on a physical examination and bloodwork results, the healthcare team will determine and administer individualized care that may include an infusion of hypertonic saline (i.e. a suped-up salt solution)10Nagler E et al (2014) Diagnosis and treatment of hyponatremia: a systematic review of clinical practice guidelines and consensus statements. BMC Medicine. 12:231. Accessed on 7/20/15 from to help normalize the blood sodium levels in a safe and effective way. Since I’d prefer to stay out of the hospital (and I’m sure you do too), I’ve done some Nancy Drew-ing (A.K.A. sleuthing) and found evidence-based ways we can stay properly hydrated during our favorite sporting events. Here are my three faves:

1. Identify if you’re at high risk for hyponatremia.

Consider these questions:

  • Am I engaging in a longer (> 3-4 hours) endurance-based activity (running, cycling, etc.)?
  • Do I sweat a lot?
  • Is my sweat really salty?
  • Do I drink a lot of water (> 3 gallons) at one time before and during strenuous activity?

If you answered yes to any of the questions above, planning how you will properly hydrate before, during and after your sport is incredibly important.

2. Don’t overhydrate.

Aren’t you so sick and tired of hearing “Not one size fits all when it comes to nutrition?” Well, I am too, and I’m sorry to say it again.  However, because everyone’s hydration requirements are different, you need to be able to calculate yours based on a variety of individualized factors11 Speedy DB, et al (1999). Hyponatremia in ultradistance triathletes. Medicine and Science in Sports Exercise. 31:809-815.. However, here’s a general guideline for water intake before, during and after activity12Whitney E and Rolfes S. (2013) Understanding Nutrition. Instructor’s Edition. Wadsworth Cengage Learning. 454.:

When to Drink Amount of Water
2-3 hours before activity 2-3 cups (16 -24 oz)
15 minutes before activity 1-2 cups (8 – 16 oz)
Every 15 minutes during activity ½ to 1 cup  (4-8 oz)
After activity 2 cups for each pound of body weight lost


Ever weighed yourself before and after a workout and got totally jazzed that you dropped some pounds? Before you go to slip on your uber-fitted LBD, remember that weight loss reflects water lost, not those few pesky pounds that have been hanging around your mid-section. (Sorry, I totally didn’t mean to burst your bubble there.) And as good as it feels to see an instant weight loss on the scale, those water losses should actually be replaced immediately after your workout.  I know, I know… don’t shoot the messenger. To replace water losses during exercise13International Olympic Committee (2010). Nutrition for Athletes. Accessed on 6/25/15 from

  1. Weigh yourself immediately before your workout
  2. Get your workout on
  3. Weigh yourself immediately after your workout
  4. Subtract weight after exercise from your weight before.
  5. Consume 2 cups (16 fluid ounces) of water per every lost pound

Example: Weight before: 122 pounds Weight after: 120 pounds 122 – 120 = 2 pounds 2 pounds x 2 cups = 4 cups of water

3. Don’t forget the electrolytes, especially sodium.

For most, sodium losses during exercise exceed those of all other electrolytes.  Therefore, it’s incredibly important to consume sodium before, during and after you finish that killer workout, especially if it lasts longer than one to two hours14International Olympic Committee (2010). Nutrition for Athletes. Accessed on 6/25/15 from  My favorite way to drink additional sodium before a long training run? Pickle juice! So, follow the steps listed above to determine how much weight you lost, and then determine how many milligrams you need to adequately replenish your sodium stores.  Check out the nutrition facts of your favorite sports drink or fermented foods and get your needs met!

How are you going to properly hydrate for your next endurance activity!?

Tagged with
cycling hydration running sports nutrition the deconstructed dish

Jenn Randazzo, MS RD

Jenn Randazzo works at Vega as a National Educator. She is passionate about building relationships that help people take ownership of their health. As a registered dietitian, she specializes in using client-centered techniques to guide people toward realistic and achievable goals. A strong believer in collaboration, she hopes to change the world through plant-based nutrition.