When you run, you’re not just sweating out water—you’re also losing key minerals your body relies on to keep your muscles firing, among other key physiological processes. These minerals, known as electrolytes, do everything from supporting hydration levels to fending off mid-jog cramps. 

But there are some electrolytes that runners may want to pay special attention to before, during, and after your miles. We spoke with two dietitians who specialize in running nutrition  about which electrolytes you may want to prioritize next time you pound the pavement or hit the treadmill—plus how to make sure you’re getting enough of them.

Why Electrolytes Are Important for Runners

We all need balanced electrolyte levels to survive—they help our bodies maintain proper fluid balance, stay hydrated, regulate muscle contractions, and keep our energy steady, according to Kristy Baumann, RD, a registered dietitian and owner of Marathon Nutritionist. Electrolytes are key players in keeping our vital organs working, from our hearts to our lungs to our brains. Without them, our bodies wouldn’t function properly. 

That’s why we need to re-up after sweating these electrolytes out during a long, vigorous workout or while exercising in hot, humid conditions. Both of those factors are often the case when we go for a run, which makes replenishing electrolytes all the more important. 

“Both fluids and electrolytes play a key role in helping long-distance runners stay properly hydrated for both performance and recovery,” says Emily Moore, RD, a registered dietitian and run and strength coach of Dietitian for Runners. If electrolytes become too depleted, we’re more likely to feel fatigued, experience heavy legs, and struggle running in the heat, Baumann adds.

Key Electrolytes for Runners to Focus On

There are seven main electrolytes in your body, but a handful of them are especially important for runners to pay attention to: sodium, chloride, potassium, magnesium, and calcium. That’s because these are the five electrolytes we lose through sweat (along with water).

In particular, sodium and chloride are the most important electrolytes to prioritize before, during, and after a run since they are the top electrolytes lost in sweat and help the body absorb fluids, according to Baumann. (If you’ve ever wondered why your sweat is so salty, it’s because of all the salt that gets expelled along with water as your body tries to maintain its balance of sodium and water levels.) 

Chloride bonds with sodium, creating sodium chloride (what you know as table salt). That means it works hand-in-hand with sodium to maintain fluid balance to prevent dehydration, support muscle contractions, and keep energy steady, Baumann says. 

While sodium and chloride may be the main two electrolytes for runners to focus on replenishing, they aren’t the only ones worth paying attention to. “Potassium, magnesium, and calcium are lost in smaller amounts but are important for muscle contractions and recovery, and can be replenished through the foods you eat after your run and throughout the day,” Baumann says.

How Many Electrolytes Do Runners Need?

If you’re going for a run that lasts more than 60 minutes, the American College of Sports Medicine (ACSM) recommends having 300–600 milligrams of sodium per hour while you work out (and runners who have salty sweat or generally sweat more may need more). 

“Drinking only plain water during long runs and races is risky, so including sodium in your plan is key,” Moore says. She generally recommends adding a sodium-rich electrolyte powder to your water or taking higher-sodium gels, capsules, or chews. (Just be sure to read the labels, since sports products have different amounts of sodium.)

What about chloride? While you can find chloride in foods like olives, seaweed, celery, and lettuce, most of our dietary chloride comes from salt—meaning when you eat foods or drinks that contain sodium, you’re generally also consuming chloride. 

All this in mind, electrolyte needs are one of the most individualized parts of fueling. “It really depends on your sweat rate, how salty of a sweater you are, the heat and humidity, and the length and intensity of your run,” Baumann says.

“Every runner has a unique sweat rate (the amount of sweat lost per hour of exercise) and unique sweat sodium concentration,” Moore adds. “Some athletes sweat heavily and lose a lot of sodium, while others have lower sweat rates and a lower sweat sodium concentration.”

To dial in your personal hydration plan, she advises doing a sweat test, which can help you determine both your sweat rate and sweat sodium concentration. From there, you can create a very specific hydration and electrolyte plan for your runs and any upcoming races. 

“Environmental factors like heat, humidity and high altitude can further increase fluid and electrolyte losses, especially during long or intense workouts, so keep this in mind when designing your hydration strategy,” Moore says.

But more electrolytes aren’t for everyone. Some experts recommend that folks with a history of high blood pressure or kidney disease avoid electrolyte supplements, for example. If your doctor has advised you to restrict your sodium intake, you should consult with them on how you can meet your fluid and electrolyte needs while running.

How and When Should Runners Replenish Electrolytes?

We know by now that you need electrolytes for a long or humid run, but just when exactly do you need them? Mapping out your intake before, during, and after can make all the difference in your performance and recovery. 

A small study published in 2021 found that male participants who took electrolyte supplements before and after an exhaustive treadmill workout performed better, noticed less exercise-related fatigue, and were better able to retain water. 

But your electrolyte refueling strategy will also depend on a few additional factors, like what kind of run you’re going for and any personal health conditions. Here are a few things to keep in mind as your run progresses.

Before a Run

Generally speaking, consuming electrolytes before working out helps prepare your body for exercise and future disruption to its electrolyte balance—especially if you’re readying for a more intense activity like endurance running.

If you’re running in the heat, are a salty or heavy sweater, or are preparing for a long race, both Baumann and Moore recommend having an electrolyte drink ahead of time. Moore says drinking one the night before and again the morning of your run can help you optimize your hydration. “The goal is to go into all of your workouts and races well-hydrated to avoid starting in a deficit, as dehydration can negatively impact performance,” she explains.

During a Run

If your run will last more than an hour, Baumann says you might want to consume electrolytes, particularly sodium, while you’re running to help your body maintain evenly balanced levels. This is also beneficial during longer speed workouts or even during short, hot summer runs, she adds. 

Again, a sports drink might be best here. Look for options that provide both carbohydrates and sodium. “The carbohydrates can help runners get in some extra fuel before a workout or race and can help a runner hit their fueling goal during running,” she says. “The sodium can help runners optimize their hydration beforehand and can help a runner meet their hourly sodium targets during exercise.” (If you’re looking for guidance on how much sodium to consume, remember the ACSM’s recommendations mentioned earlier: Aim to have about 300–600 milligrams per hour during long workouts.)

Not a fan of sports drinks or won’t have one accessible during your run? You can also use chews or gels with added electrolytes, or opt for electrolyte tablets and drink them with water every 30–45 minutes, she adds. 

After a Run

Replenishing electrolytes after running helps restore what you’ve lost in sweat during your workout. They should be included as part of your recovery meal with carbs and protein, Moore says. She recommends having a glass of chocolate milk, which naturally contains all three, or a recovery shake to rehydrate and refuel.  

But you can also add electrolyte-rich foods to your plate—and it’s a smart idea to include them in your everyday meals and snacks anyway, Moore says. She breaks down a few of her favorites:

Don’t forget to drink plenty of fluids, either. After an extended workout (think: runs lasting 60 minutes or longer), experts generally recommend having 24 ounces of water for each pound of body weight you lose from sweat. 

The Takeaway

We all need electrolytes, which are minerals essential to keeping our bodies functioning—but we especially need them after an exhaustive exercise like running. That’s because our bodies sweat out electrolytes (along with water), particularly during a long, intense, or hot and humid run, possibly creating an electrolyte imbalance. 

Of the five electrolytes we lose through sweat, we primarily need to focus on replenishing sodium and chloride when we run. That’s because they’re the top two electrolytes we lose when sweating and they help our bodies absorb fluids. While the amount of electrolytes runners should consume is individualized, a general rule of thumb to aim for is 300–600 milligrams of sodium during runs that last more than an hour.

Consuming electrolytes before a run helps our bodies prepare for an electrolyte disruption; having them during a run helps maintain evenly balanced levels; and replenishing them after a run helps restore what’s lost. Electrolyte drinks; chews, tablets, or gels; and good old-fashioned food will all do the trick, but timing them for consumption depends on your individual needs.