The 411 on Electrolytes

Electrolytes are advertised on so many products these days – even your local 7-Eleven is chock full of ‘em. So what’s the story on electrolytes when it comes to running performance? Are you getting the right balance? How do you determine the electrolytes you need when training and racing?

Electrolytes Explained

First off, what are these magic “electrolytes”? A group of minerals crucial to your muscle function and proper hydration, electrolytes are involved in the transmission of electrical impulses that signal muscle contraction and relaxation. The electrolytes commonly utilized by the body are sodium (Na), chloride (Cl), potassium (K), calcium (Ca), and magnesium (Mg), all commonly found in the foods we eat everyday.

Why You Might Need More

Electrolyte deficiency can cause all kinds of problems with your performance, including nausea, fatigue, cramping, vomiting, and weakness. A balanced diet will supply the body with enough electrolytes for day-to-day functioning. However, you may need greater electrolyte levels during runs. Since you lose electrolytes through sweat, the longer the run and/or the hotter the day, the more likely you will need to replenish your electrolyte stores on the run.

Finding the Right Balance

Knowing when your electrolyte levels are optimal can be tricky, and finding the right balance is often a process of trial and error. Few runners need electrolyte supplements for runs in mild or cold conditions, or runs under 60 minutes. But there are many cases, such as longer runs in hotter weather, when an electrolyte supplement can help. Also, some runners naturally sweat more than others, and will deplete electrolytes faster.

Runners who are regularly out more than an hour may benefit from a sports drink containing both electrolytes and carbohydrates to refuel the body for sustained activity. But note that fluids with a high concentration of electrolytes and carbohydrates may cause gastrointestinal distress for some runners.

You might want to use a sweat loss calculator and track your sweat rate at different temperature/humidity combinations for a better understanding of how much fluid and electrolyte intake you need. Since no two runners are the same, you’ll have to put in a bit of work to figure out your optimal intake.

Replacing Lost Electrolytes
So if you want to replenish electrolytes, what are some of your options? Before you head out, build your electrolyte levels with coconut water, a good natural source of electrolytes, or add a bit of salt or a drink mix powder to your favorite drink. On your run, you may want to consider:

  • Drink Mix: A good choice to replenish lost fluids and gain energy, a drink mix powder is preferred to a ready-to-drink, because most ready-to-drink products are high in simple sugars, which are broken down and digested quickly. Fluid Performance and GU Brew are popular options containing both carbohydrates and electrolytes. For an electrolyte-only drink, choose Hammer Endurolytes Powder.
  • Capsules: If you prefer to drink water because a drink mix upsets your stomach, or you need a greater amount of electrolytes, you might want to try Succeed S!Caps for electrolytes or SaltStick Caps PLUS for electrolytes with caffeine.
  • Tablets: If you don’t need fuel but do need water and electrolytes, tablets conveniently dissolve in water. They’re easily stowable for longer runs. The Nuun 4 Flavor Variety Pack offers a nice range of flavors.
  • Gels and Chews: Although providing electrolytes is not the main purpose of these types of supplements, you’ll find electrolytes on the ingredient list of most gels and chews. If you’re looking for electrolytes, Clif added 3x the sodium to the Margarita flavored Clif Shot Bloks Energy Chews 18-Pack.
  • Jeff Gaudette

    Thank you for linking to our sweat loss calculator! A very useful tool, especially in the summer, and a helpful way to balance electrolytes.

  • Matt

    Thanks for a super-helpful tool Jeff. Happy running!

  • Jim

    Numerous well-done scientific studies have indicated that these products have no effect on the levels of electrolytes in our bodies. And this post only promotes the pseudo-science that helps sell them.

  • Alice

    Thanks for your comment, Jim. We’d love to see the studies you’re referring to. If you have the links, could you send them our way?

  • Jim

    Clin J Sport Med. 2002 Sep;12(5):279-84.
    Oral salt supplementation during ultradistance exercise.
    Speedy DB, Thompson JM, Rodgers I, Collins M, Sharwood K, Noakes TD.
    This study concludes that salt supplementation during an ironman has no effect on blood sodium levels.

    Br J Sports Med. 2006 Mar;40(3):255-9.
    Sodium supplementation is not required to maintain serum sodium concentrations during an Ironman triathlon.
    Hew-Butler TD, Sharwood K, Collins M, Speedy D, Noakes T.

    Br J Sports Med. 2011 Jun;45(8):650-6. Epub 2010 Dec 9.
    Increased running speed and previous cramps rather than dehydration or serum sodium changes predict exercise-associated muscle cramping: a prospective cohort study in 210 Ironman triathletes.
    Schwellnus MP, Drew N, Collins M.

    No well designed field study has ever shown salt supplementation to have benefits for performance, heat stress, muscle cramping, electrolyte levels or energy.

    Caffeine has been demonstrated to have some ergogenic benefit, however.

    Just trying to show the lack of science behind some claims….

  • Alice

    Thank you for passing these references to us, Jim. We’re going to share them with our nutrition vendors and get their insights as well. The bottom line for us is making sure that we’re providing products that will help our customers on their runs.

  • Henrik Damslund

    I would also suggest you take a look at Tim Noakes book – Waterlogged. He has all the prof and references you need.

  • Matt

    We checked in with the manufacturers of SaltStick, one popular electrolyte capsule on the market. They directed us to an article about sodium and fluid intake and loss over time, and how the concentration of electrolytes can increase and decrease depending on fluid intake. The article is here:

    They also mentioned that research to date does not differentiate between serum sodium levels and sodium content in the body as a whole, whereby electrolyte levels are regulated between plasma and tissue. And they added that very few studies take into account the loss and replacement of other essential electrolytes. Research is ongoing in these areas, for example Doug Casa (University of Connecticut) conducted experiments at the 2011 and 2012 Ironman in Kona, HI with results pending.

    Their take is that the guiding principle of not over-drinking appears to be sound, and over the course of extended effort, some measure of replacement of both fluid and sodium are required, since the content of both of these essential components in our bodies is limited, and will be depleted over time.