Electrolytes: what sodium and potassium actually do

"Electrolyte" is a word that sells sports drinks, but the actual chemistry is calmer than the marketing. Electrolytes are just minerals that carry a small electrical charge when dissolved in the body's fluids — and two of the most important, sodium and potassium, come mostly from ordinary food.

Key takeaways

• Electrolytes are charged minerals that help manage fluid balance, nerve signals, and muscle function.
• Sodium and potassium are the two big ones for everyday balance, and they work as a pair.
• Most people get plenty of sodium and too little potassium — the opposite of what the drink aisle implies.
• For typical daily activity, food and water cover electrolyte needs; special drinks are the exception, not the rule.

What electrolytes do

Dissolved in blood and the fluid around your cells, electrolytes keep several everyday systems running: they help balance how much water sits inside versus outside cells, they let nerves fire, and they help muscles contract and relax. Sodium and potassium do a lot of this work together — sodium tends to hold water and sit largely outside cells, potassium sits mostly inside them, and the balance between the two is what matters.

The main electrolytes at a glance

The everyday story is mostly the top two rows.

The part the drink aisle gets backwards

Here's the twist. In the U.S., the common problem isn't too little sodium — it's too much. The Dietary Guidelines flag potassium as a nutrient many people fall short on, while sodium intake tends to run high, largely from packaged and restaurant food rather than the salt shaker. So for most people, the useful move isn't adding an electrolyte drink; it's eating more potassium-rich whole foods and going easier on ultra-processed, high-sodium ones.

FAQ

Do I need an electrolyte drink?

For ordinary daily activity — including a normal workout — water and regular meals generally cover it. Electrolyte drinks make more sense in specific situations: prolonged, intense exercise (think well over an hour, especially in heat) or heavy fluid loss from illness. Outside those cases, they're mostly flavored sodium and sugar you don't need.

Isn't more sodium good for hydration?

Sodium does help your body hold onto water, which is why it's in rehydration formulas. But most people already get more than enough from food, so "add salt to hydrate" isn't useful general advice for typical days.

What about "natural" electrolyte waters?

Labels like "natural" or "enhanced" aren't a nutritional guarantee. If you want the electrolytes food already provides, potassium-rich produce does the job without the marketing.

For most people most of the time, electrolytes aren't something you buy in a bottle — they're something a balanced plate and a glass of water already deliver.