Base Knowledge: Electrolytes

We're told that they matter--but what are they and what do they do?

The Upshot, Upfront:

• Electrolytes are minerals, including sodium and potassium, that serve a number of functions in your body. You sweat them out.

• Sports drinks containing electrolytes can be useful for hard efforts over an hour long, but mostly you get the electrolytes you need from a balanced diet.

For some reason, sports drink makers have a rough time explaining electrolytes. Sure, they tell us that we need them, but they rarely (if ever) tell us what they are.  

800-pound sports drink gorilla Gatorade has made a few attempts over the years but never quite nailed it, bless their FD&C yellow 5-stained hearts. There’s an ad from the 1970s vaguely explaining their drink contains “potassium, fluids, minerals,” but beyond that, they seemed content to state that “research men” created Gatorade, that it’s trusted by athletes, and that it’s ideal for use while mowing the lawn.

(In all fairness, Gatorade does run a pretty neato online exercise research repository called the Gatorade Sports Science Institute, but it’s not really known for its accessibility.)

In the mass media, you don’t hear much explaining what electrolytes are. Perhaps that’s because the gen pop doesn’t really care. Or maybe only research men should possess such arcane knowledge.

Either way, humanity is left with a vague general awareness of electrolytes that sets us up for an Idiocracy-style end to the human race.

But we can fix that. Electrolytes are not that mysterious. They’re minerals, including sodium and potassium, that serve a number of functions in your body—and you expel them when you sweat. If you sweat a lot over prolonged periods, it’s not a bad idea to drink something containing electrolytes.

That’s the basics. Now, if you want to prepare should you end up on Jeopardy and one of the categories is “Electrolytes,” read on.

Electrolytes for $1000.

Sodium, magnesium, potassium, calcium, chloride, phosphate, bicarbonate, and sulfate are all electrolytes found in the human body. They’re minerals that dissolve in water, generating an electrical charge that helps cells accomplish various bodily functions such as regulating fluid levels, maintaining blood pH, and allowing muscle contractions.

Sodium, magnesium, potassium, and calcium are cations, meaning they have positive charges. Chloride, phosphate, bicarbonate, and sulfate are anions, meaning they have negative charges. Cations and anions pair up. For example, positive sodium combines with negative chloride, making sodium chloride—or table salt.

Electrolytes also work in tandem on a broader scale. Sodium and potassium work together to keep cell fluid levels in check. Sodium pulls fluid into cells and potassium dumps it out. This “sodium-potassium pump” also flushes waste products out of cells, which is a nice little bonus.

Calcium and magnesium are another example of an electrolyte pair. Together, they regulate nerves and muscles. Calcium activates nerves but magnesium blocks calcium, allowing nerves to relax. Anecdotally, if I’m having tight muscle issues, which isn’t uncommon for us athletic neurotic types, magnesium is my go-to muscle relaxant.

Do you really need electrolytes?

Yes, you do. You know the phrase “essential vitamins and minerals”? Electrolytes make that list.

While it’s true that you sweat out electrolytes, it’s not that important to replenish them immediately in most situations. You should already be getting ample electrolytes from the foods you eat. Here are a few examples:

• Potassium: bananas, lentils, and potatoes.

• Magnesium: raw seeds, nuts, whole grains, and leafy greens.

• Calcium: sardines, tofu, spinach, and dairy.

• Sodium: I’ll let you figure this one out.

Electrolyte sports drinks really only matter if you plan to sweat heavily for more than an hour. (Some experts say 75 minutes.) While this helps restore lost minerals (mostly sodium), the main reason to drink a sports drink containing electrolytes and carbohydrates is that it’s been shown to increase the absorbency of the water. To be clear, if you drink plain water, you absorb some of it. If you drink water plus carbs and electrolytes, you absorb more of it.

Also, salt and sugar make things taste yummy, so you’re inclined to consume more. During a hard workout, that’s a good thing.

Keep in mind that the absorbency thing only applies to hypotonic or isotonic sports drinks. I’ll explain this in a future newsletter. In the meantime, this video from GCN does a pretty good job.

I know a lot of people believe they need to take electrolytes (salt tabs, for example) to prevent cramping. The research men tend to debate this one. Some say cramps come from fatigue. Others blame a lack of electrolytes. I’d put my money on a combination of both.

Practical recommendations.

Most of the time when I train, I use plain, ol’ water. I’ll use a sports drink on longer runs and rides if I plan to work hard and/or if it’s really hot. Everyone sweats differently, so it’s a matter of personal need. If you want to geek-out, Gatorade makes a one-and-done Gx Sweat Patch that measures the sodium in your sweat and makes recommendations. Nix Biosensors makes a longer-term solution featuring patches and app that also track electrolyte losses.

Still, the best source for information regarding how you should use electrolytes is you. If you use salt tabs because you’ve experienced the benefits firsthand, keep it up! But if you drink a fancy sports drink because the marketing team at Brawndo (The Thirst Mutilator!) insists that’s what you crave, maybe give it some additional thought.