Is the Answer More Sodium? Breaking Down Hydration for Endurance

Table of Contents

• Hydration for Endurance Quick Start

• Introduction

• Signs and Symptoms of Imbalance between Fluids and Electrolytes

• Ways to Take in Sodium

• Where to Start

• The Recommendation

• Conclusion

Sodium is undoubtedly one of the most talked about additions to any endurance athletes' toolkit. For good reason, too, as sodium plays a key role in fluid balance. And, since it’s the primary electrolyte lost in sweat, replacing it as you exercise becomes a top priority due to the sweat losses during activity.

That said, is more better? Should we be getting in as much as possible? Where’s the limit? 

Hydration for Endurance Quick Start

• Aim for 14-18 ounces of water per hour of exercise as a start, depending on how much you feel you sweat. Ie. if you're drenched at the end of a workout, aim for 18 ounces per hour.

• Pair this with 300-600mg sodium per hour of exercise, depending on how salty of a sweater you are

• Choose your favorite electrolyte solution from powders, gels, chews, and capsules

• Sip fluids every 10 minutes as you get going to build the habit

• Adjust based on body cues and conditions (eg. heat, humidity, altitude)

Introduction

While sodium often takes the spotlight, it’s one of several electrolytes that help to maintain fluid balance, nerve signaling, and overall metabolic function in the body. Chloride, potassium, calcium, and magnesium all play key roles, too.

You might be asking yourself why does sodium get so much attention if there are more electrolytes to also consider. The reasons are quite simple. You lose more sodium in your sweat than almost any other electrolyte, and sodium plays a key role in retaining the fluids you take in. As a result, it becomes the primary focus for electrolyte replacement during extended exercise. This is why many sports nutrition products now have ample levels of sodium within them to support endurance athletes’ losses during prolonged exercise, ultimately aiding performance.

That said, we can’t talk about electrolytes without also talking about water. 

While many factors can influence total body water in an individual, on average over half of the human body is made up of water, depicting how vital it is to our lives.

When you exercise, you also increase core body temperature. Sweat is your body’s natural response that helps to cool you down. You can lose copious amounts of water and electrolytes (mainly sodium) through this mechanism. Thus, the warmer and more humid the conditions are, the more we also sweat.

It’s easy to see marketing for hydration beverages and think that simply taking in more sodium is the solution to many of the problems we may come across as endurance athletes. We’re here to question that.

In reality, hydration depends more on sodium and water working together. Yes, you need electrolytes, including sodium, but you likely don’t need 1,000+ mg of sodium every single hour, especially if you’re not getting enough fluids first. In many cases if you’re under-consuming fluids, first focus on achieving adequate fluids before increasing sodium. This will not only be more effective, but will also support what the body truly needs with less risk of imbalance and negative symptoms.

Signs and Symptoms of Imbalance Between Fluids and Electrolytes

We’ve set the stage to understand that as we exercise, we lose fluids and electrolytes through our sweat. The complex part about this is that everyone has a different sweat concentration, meaning how much fluid and electrolytes your specific sweat contains per liter, and sweat loss rate, meaning how much actual sweat your body gives off in terms of volume in liters per hour. 

In general, the goal is to avoid losing or gaining more than 2% of your body weight during exercise. While this may sound easy in practice, it’s much more challenging to put into place because of how much fluids we stand to lose each hour of exercise, especially taking into consideration factors like heat and humidity, where losses go up even further. We say this to tell you that you’re not alone if you’ve had challenges here.

Many professionals in the same recommend utilizing numbers, like sweat tests and/or weighing pre- and post- workout to help understand needs. While this can certainly provide valuable information, it shouldn’t be the only information an athlete relies on as it can make an individual hyper-focused on these results, using them as the sole guide during exercise. The problem with using these numbers alone is that the results are tied to the specific conditions they exercised in, so it may not always be applicable.

Often overlooked is arguably one of the best tools we have, our own body cues. Bodies give incredible cues to help navigate hydration, we just simply have to tap into them. 

What to watch for as indicators you may need to adjust your fluids and sodium, either increasing or decreasing depending on the symptoms:

• Sloshy stomach

• Seeing stars

• Dizziness

• Lightheaded

• Confusion

• Blurry vision

• Cramping

• Fatigue

• Bathroom urgency or changes to texture/consistency

• Headaches

If you’ve ever experienced any of the above at any point during a training block or race, you might want to circle back to your hydration and make some adjustments. The goal is to use these symptoms as a guide, alongside the general recommendations we’re going to provide, to help you better understand what those body cues are telling you. 

This helps you tune into how you’re feeling, rather than relying on numbers before/after exercise to navigate your hydration needs. The reason being that on race day, numbers alone won’t be able to get you to the finish. What will get you there is understanding your body cues, knowing that if a cue is given, you'll know exactly how to handle it.

Taking in adequate hydration (both fluids and electrolytes) during exercise can help with many different metabolic processes, including the maintenance of heart rate, perceived exertion, and core body temperature, allowing you to push harder and feel good during your workouts and races.

Ways to Take in Sodium

There are now many creative ways to get in all the sodium the body needs. Having multiple options is fantastic for athletes, because that means the main continued challenge is finding creative and easy ways to get in enough fluids. Let's face it, we all dread carrying bottles while we run, but we know we have to in order to support fluid intake!

When it comes to electrolytes, there's no best option as a blanket statement. This is because the best option is the one you’ll consistently use. Thus, finding the flavor and texture you enjoy is key. And, since there are multiple options to choose from to help you meet your needs, the individualized nature of hydration shines through:

• Electrolytes in powders: both on their own and with carbohydrates

• Gels that contain electrolytes: the most dynamic and creative of the options, this contains all the carbs and sodium an athlete could need each hour, leading them to just need water to round out their during exercise requirements

• Electrolyte tablets: contain sodium and, in many cases, additional key electrolytes, too.

• Electrolyte Chews: a category loved by many athletes, as these can support intake without needing to swallow the actual capsule as you exercise

Pick the option that sounds best to you from the above and start to implement at a moderate intake, which we’ll discuss in detail below. 

Where to Start

If you’re having trouble choosing an option. Don’t worry, we’ve got you! Use the below as a guide. 

First, think about your preferences. Ask yourself:

• Am I someone who likes to carry a bottle on me? 

• If yes, potentially a carbohydrate and electrolyte powder could be a good option so you don’t have to also carry gels. 

• If no, potentially we’d want to turn toward gels with electrolytes so you can rely solely on the water fountains on your route, and not have to worry or time your intake of sodium capsules to a fountain.

• Would I enjoy having water alongside my gels? Or would I enjoy having something more sweet consistently?

• If you’d enjoy water more, test out gels with electrolytes 

• If you’d enjoy a beverage with some flavor, go for a carbohydrate and electrolyte powder, or if you enjoy taking in original gels without electrolytes, go for an electrolyte powder in your bottle

• Can I swallow capsules while running, especially at higher intensities?

• If yes, this could be an option alongside your gels and water

• If no, stick with powders, liquids, and gels.

• Does a chew that you can use almost like a lozenge sound good? 

• This is one to consider if you also get dry mouth as they can sometimes help stimulate saliva due to the more acidic/sour tasting flavors

Based on the above questions, you should arrive at a starting point for the delivery of your sodium and fluids. 

The Recommendation

Our recommendation is to aim for 300-600mg of sodium and 14-18 ounces water per hour of exercise when you’re doing endurance-based activities for over 55 minutes in duration as your first goal.

If you find you’re a heavier or saltier sweater, aim for the higher end of the ranges as you get going, and adjust from there. 

When you begin testing this in practice, be sure you work to sip on fluids every 10 minutes to build a good cadence.  Avoid drinking larger volumes of fluids all at once, a tendency for many endurance athletes. Smaller, more frequent sips are generally easier on the GI and support steady absorption with less risk of negative symptoms.

If you find yourself without any of the above symptoms after your runs over multiple weeks, that likely means you are in a great spot for your hydration. 

Conclusion

Hydration isn’t about chasing the highest sodium intake. It’s about doing a delicate dance with both sodium and water to find the most optimal balance for your body. Needs will vary, so try not to compare yourself to those around you. 

Start with fluids, pair them with a sodium of choice using the decision tree to help guide you, and use your body’s awesome feedback mechanisms to help you tinker from there. The goal isn’t to do what someone else is doing, it’s to develop your own personalized strategy that you can trust to keep you feeling empowered in training and racing.