A Quick Primer on Electrolytes for Runners

The promises of electrolytes almost seem too good to be true: better hydration, faster finish times, lower chance of muscle cramps, and less risk of ending up in the med tent. The research supports all of these, though, which is why runners need electrolytes! 

Electrolytes are essential for summer running and long-distance racing (and particularly for summer long runs!). Some runners are salty sweaters and may benefit from electrolyte supplementation year-round. Other runners may only need them for summer or long-distance races. You are not just limited to Gatorade; numerous options of electrolyte hydration mixes and tablets are available on the market, so you can find the one that works best for you! 

A Quick Primer on Electrolytes for Runners

What are Electrolytes and Why are They Essential for Runners?

Electrolytes are naturally occurring minerals found in your sweat and urine that your body uses to conduct electrical charges. This electrical charge is responsible for muscle contraction and relaxation, fluid balance, and neurotransmission between the brain and muscles. Electrolytes include sodium, potassium, magnesium, and calcium. It is important to replace all of these, which is why just plain salt is not fully effective (although it is better than plain water!).

For daily function, whole foods can provide the necessary electrolytes. However, endurance athletes have higher electrolyte needs, particularly during long-distance races, long runs, and summer training. Thus electrolytes need to be replaced during runs through easily absorbable means – such as sports drinks or salt tablets. 

On average, you generally lose 800mg of sodium, 195 mg of potassium, 20 mg of calcium, and 10 mg of magnesium per hour of running. This will vary of course depending on the temperature, your own sweat rate and sodium loss, and the intensity of your workout. You are not going to replace this completely; the optimum goal is roughly half of this (so roughly 400mg of sodium per hour of intense exercise). You do want to be mindful not to overdue the sodium, as too much can cause excessive thirst and GI distress. So, don’t take both Nuun AND Saltstick; however, combining gels and Nuun or Skratch works well for most runners. 

In long-distance races, electrolytes can serve as an ergogenic aid (performance booster). A 2016 study in the Scandinavian Journal of Medicine and Science in Sports tested triathletes in the half marathon distance, with a control group (who took placebos) and a group consuming oral electrolyte tablets. The electrolyte group finished an average of 26 minutes faster than the control group. That’s a significant amount of time!

Electrolytes Aren’t Just For Salty Sweaters

A 2011 cross-sectional study in the Journal of Athletic Training found that marathon and half marathoners runners a majority of runners (particularly female runners) preferred the taste of water to sports drink and avoided sports drink due to the calorie count. Real-life coaching experience supports this; both myself and other coaches I know have seen athletes either forget to take or deliberately avoid electrolytes consumption. 

But for long-distance running, electrolytes are essential for both performance and heallth. Minor electrolyte imbalances can cause muscle cramping and dehydration; severe imbalances can cause nausea, vomiting, confusion, dizziness, and even seizures as symptoms of dilution of the blood (hyponatremia). 

Common misconceptions tend to correlate heavy sweaters with a lack of fitness. While it is true that an unfit athlete will sweat more at lower exertion levels, sweat rate is simply an individual factor. Some runners simply sweat higher volumes and lose more salt in their sweat, even if they are highly trained. According to a 2016 study in the Journal of the International Society of Sports Nutrition, approximately 20% of non-professional marathon runners are salty sweaters – and no individual characteristics or past training predicts one’s sweat rate. 

Now, it is worth noting that you want to take in electrolytes even if you are not a salty sweater. According to a 2015 study published in the Scandinavian Journal of Medicine and Science in Sports, while salty sweaters tend to have lower sodium serum levels, any runner is at risk for hyponatremia if they overhydrate and do not replace sodium during a long-distance race. As the study noted though, salty sweaters need to be extra cognizant of taking in higher levels of sodium during exercise. 

The Risks of Electrolyte Loss for Runners

  • Performance Decline: Electrolytes support performance in a two-fold manner. First, they encourage proper fluid absorption. Hydration supports performance through a variety of mechanisms, including core temperature control and optimal blood volume. Electrolytes also contribute to proper muscle fuction. 
  • Muscle cramping: Electrolytes play a role in muscle contractions; thus low electrolyte levels increase the likelihood of poor muscle functioning – including muscle cramps. According to a 2021 study in the Journal of the International Society of Sports Nutrition, not only does drinking fluids with electrolytes decrease the incidence of cramping – but consuming plain water during long-distance running actually makes you more likely to experience muscle cramps. 
  • Hyponatremia: When you consume too much water during exercise but do not replace your electrolytes, your blood volume can become too diluted with water. This condition is called hyponatremia and requires immediate professional medical care. Symptoms include nausea, vomiting, dizziness, confusion, headache, and intense fatigue. 

How to Consume Electrolytes

Most runners skip electrolytes because Gatorade upsets their stomachs. However, it is not the electrolytes causing GI upset; it’s the high levels of simple sugars and the artificial coloring and flavorings.  There is nothing wrong with drinking Gatorade or Powerade if it works for you. However, if you are one of the many runners who find Gatorade causes GI distress, you will want to find an alternative option and carry it with you on your training runs and race day. 

If you are running for less than an hour, you do not need to take electrolytes. For runs longer than an hour and races in the 1-3 hour range, you want to take a hydration mix or electrolyte tablet. For races exceeding three hours, be extra mindful of consuming adequate electrolytes both before and during; marathon runners with hyponatremia often began in a slightly electrolyte-deficient state

Most electrolyte drinks formulated for exercise will contain carbohydrates. Carbohydrates play a key role in sodium transportation into the muscle cells. Considering that the recommendations for long runs and races are 30 to 60 grams of carbohydrate per hour, those extra carbs will only help! 

Some popular options include:

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Do you take electrolytes on runs? What’s your go-to hydration mix?

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10 Responses

  1. I have used Tailwind with good success for many years. I did find that even diluted, it sometimes upset my stomach. I’ve had issues with gels too. I just got a sample of Liquid IV to try and I’m looking forward to seeing how it works for me.

  2. This is great information, Laura. I like how you broke it down in an easy-to-understand manner.

    I’m planning to make my own electrolyte concoction. It’s cheaper and I know what’s in it.
    I’m not sure if I’ll succeed – I’ll keep you posted!

  3. Thanks for the info.

    I tend to drink just plain water.

    I eat Gu which does contain electrolytes.

  4. Super helpful, thanks, as we approach summer. I can do the powders better than I can gels, although I love the margarita chews, which I think have some salt. Really need to look into the salt sticks.

  5. I’ve been using Liquid IV lately which I am liking. I fill one smaller water bottle with plain water and the other with Liquid IV for my long runs (and put them in the front of my hydration vest). Adding some electrolytes can really make a big difference, especially on summer long runs!

  6. Electrolytes are so important! I personally love Nuun Hydration too and always have a few tubes in the house. I remember after my very first half marathon I visibly had salt on my face from sweating out so much salt. It’s so important to replenish!

  7. Electrolytes have really helped me with my post-run fatigue! I used to feel terrible after long runs until I discovered the power of electrolytes. And now I take them religiously if I’m out longer than an hour.

  8. Thank you so much for sharing

    Electrolytes have really helped me fight off fatigue, especially post-training. I’ve always felt terrible after a long workout and things changed once I started paying attention to my electrolytes intake. I used to drink just plain water. Big mistake

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