This article is written by Amy from The Running Dietitian. Sweat and hydration are two words that may come to mind when hearing the word electrolytes, but these minerals do much more than just keep you hydrated.

Electrolytes are minerals that dissolve in water to form charged particles called ions, and they’re found in nearly all body fluids and cells. As they move in and out of cells, electrolytes generate electrical signals that the body relies on to regulate many vital processes and keep everything functioning properly.

When it comes to running, electrolytes are crucial for hydration, fluid balance, muscle contractions, and your overall performance.

Sweat is primarily made up of water, but it also contains electrolytes. Sodium and chloride are found in the highest concentration of electrolytes in sweat with potassium, magnesium, and calcium present in lower amounts.

When you experience dehydration, the body will struggle to regulate temperature effectively. Even a mild fluid loss can cause fatigue, slower pace, decrease in performance, dizziness, and headaches. More severe dehydration raises the risk of overheating and heat-related illnesses such as heat exhaustion or heat stroke.

Warning signs of dehydration to be aware of include dark-colored urine, urinating less often, a dry mouth, reduced sweating, or difficulty holding pace. Because sweat also contains electrolytes, significant losses can interfere with muscle contractions, nerve signaling, and fluid balance.

Low electrolyte levels can also impair performance. Symptoms may include muscle cramps, nausea, headaches, or swelling in the hands and feet. In extreme cases, drinking large amounts of water without replacing electrolytes can dilute sodium levels in the blood, leading to hyponatremia.

Most runners lose between 400 to 2,400ml of sweat per hour of exercise. Sweat loss varies based on factors such as age, sex, weight, exercise intensity and duration, and weather conditions. Much like the amount of sweat that is lost, the sodium content of this sweat can vary widely, from 115mg to over 2,000mg per liter of sweat.

Because both sweat rate and concentration vary so much from runner to runner, it can be challenging to determine exactly how much fluid and electrolytes you need. To know your exact needs, one option is to undergo a sweat test at a sports lab, such as Precision Fuel & Hydration, to get personalized data.

There are also at-home kits available, like Levelen or Nix, that provide personalized feedback. However, many runners find success through trial and error—tracking fluid and electrolyte intake, noting how they feel during and after a run, and making small adjustments over time.

Electrolytes can be consumed in several forms, depending on your preference and needs.

Electrolytes get a lot of attention in the running world, but they aren’t always necessary. There are times when plain water is all you need and times when electrolytes are necessary to support performance.

For short runs under an hour in cool conditions, for everyday hydration outside of workouts, or when your recovery meal already contains sodium and other electrolytes, water alone is usually enough.

Electrolytes become more important during runs that last over 60 minutes, in hot or humid conditions, or if you’re someone who sweats heavily and loses noticeable salt (think salt stains on your body and clothing).

That said, more electrolytes aren’t always better. Overdoing it, especially with sodium, can lead to bloating, stomach upset, and in rare cases, imbalances such as hypernatremia (too much sodium in the blood).

If you’re consistently fatigued despite hydrating and using electrolytes appropriately, you may need to look for a different cause. Under-fueling (not getting enough carbohydrates or calories), low iron, or other medical issues could be contributing factors worth checking in with a healthcare professional.

Most runners won’t need an electrolyte replacement product during races lasting under 60 minutes. However, on hot and humid days, or if you know you’re a heavy sweater, it can be helpful to replace electrolytes even during shorter efforts.

There are different types of electrolyte products from chews to gels to drink mixes. Find the product that makes it easiest for you to replenish your electrolytes.

A chewable electrolyte tablet, SaltStick FastChews can start working in as little as 45 seconds. Therefore providing a faster, more convenient way to replenish electrolytes. Two FastChews provide 100mg of sodium.

Offers 400 milligrams of sodium per scoop, along with 20 grams of carbohydrates, giving runners both electrolyte support and quick energy for longer efforts.

For an all-in-one product, look no further than E-gels. One gel provides you with 230mg of sodium and 37g of carbohydrates.

Not only does chocolate milk have the ideal ratio of carbohydrates to protein found to support recovery, it also provides electrolytes such as sodium, potassium, magnesium, and calcium.

For runners who lose a high amount of salt in their sweat, simply adding a pinch of table salt to an electrolyte or endurance drink can be an easy and cost effective way to boost sodium intake.

Hydration and electrolyte needs vary widely between runners, depending on factors like sweat rate and concentration, intensity, and weather. There isn't a one-size-fits-all approach to hydration and electrolyte replacement. The key is to listen to your body, find the replacement strategy that works best for you, and personalize your hydration strategy for optimal performance.