Electrolytes, Explained: What They Do and When You Need More
Electrolytes are minerals that carry an electric charge once they dissolve in your body's fluids. They help balance water between your cells and your blood, carry nerve signals and make muscles contract. You get almost all of them from food — which is why most people never have to think about them.
What are the main electrolytes, and where do they come from?
| Electrolyte | What it helps with | Main food sources |
|---|---|---|
| Sodium | Fluid balance, nerve signals | Salt, bread, cheese, most packaged food |
| Chloride | Fluid balance, digestion | Salt (it's the other half of sodium chloride) |
| Potassium | Muscle and heart rhythm, fluid balance | Potatoes, beans, bananas, leafy greens, yogurt |
| Magnesium | Muscle and nerve function | Nuts, seeds, whole grains, leafy greens |
| Calcium | Muscle contraction, bones | Dairy, fortified foods, leafy greens |
Most American adults eat more sodium than recommended — the FDA puts the average around 3,400 mg a day, against the Dietary Guidelines' limit of 2,300. Potassium is the opposite: many people fall short, and fruit, vegetables and beans are the fix.
Do you need electrolytes after exercise?
Sweat is mostly water, plus sodium and chloride and a little potassium. How salty it is varies several-fold from one person to the next. For a typical workout under an hour, water and your next meal replace it all. It starts to matter when:
- The session is long — over an hour or so of steady sweating.
- It's hot or humid, so you sweat far more than usual.
- You're a salty sweater — white crust on your clothes or salt stinging your eyes.
- You're drinking a lot of plain water over many hours — that's when low blood sodium becomes a risk. More on that in drinking around a workout.
In those cases a drink or snack with sodium (and carbohydrate, for long efforts) helps your body hold on to the water you drink.
What should you drink when you're sick?
Vomiting, diarrhoea and fever drain water and electrolytes together. Oral rehydration solutions from the pharmacy are made for exactly this; see a doctor if you can't keep fluids down or the signs on our dehydration page get worse.
Does bottled or alkaline water have electrolytes?
Purified water starts with almost nothing in it, so many brands add a measured blend of minerals back for taste — Alkaid does. Those minerals are electrolytes, but the amounts are small compared with a meal. Drink it because you like the taste and it's there when you're thirsty, not as an electrolyte supplement. How the minerals get added is in what alkaline water is.
This is general information for healthy adults, not medical advice.
Sources
- National Academies of Sciences, Engineering, and Medicine. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate, 2005.
- U.S. Food and Drug Administration. Sodium in Your Diet, 2024.
- American College of Sports Medicine. Exercise and Fluid Replacement (position stand), 2007.
Questions people ask
Does alkaline water have electrolytes?
Most alkaline bottled water, Alkaid included, is purified water with minerals added back for taste. Those minerals are electrolytes, but the amounts are small next to what you get from food. It's water, not a sports drink.
Do I need electrolyte drinks every day?
Most people don't. A normal diet supplies plenty of sodium and chloride, and food is where the rest comes from. They matter more for long, hot or very sweaty sessions, and during illness with vomiting or diarrhoea.
What is the white crust on my gym shirt?
Salt from sweat. If it shows up regularly, you're a salty sweater, and on long sessions you may need more sodium than people who sweat less salt.
Are electrolyte powders safe?
For healthy people, used as directed, generally yes. If you have high blood pressure, kidney disease or are on a low-sodium diet, check with your doctor first — many are high in sodium.