Electrolytes are minerals that carry an electric charge when dissolved in water. The main ones are sodium, potassium, chloride, calcium, magnesium, phosphate, and bicarbonate. Because your body is mostly water, these charged particles move through your fluids and tissues to power signals, balance fluids, and keep cells functioning.

Where They Live and Why That Matters

Body water sits in two main spaces: inside cells and outside cells. Potassium and phosphate are higher inside cells. Sodium and chloride are higher outside cells. This difference creates gradients. Cells use the gradients to move water and nutrients and to generate electricity.

How They Move

• Diffusion: Ions drift from higher concentration to lower concentration.
• Osmosis: Water follows dissolved particles. More sodium outside a cell pulls water outward, and more potassium inside pulls water inward.
• Active transport: Pumps such as the sodium potassium ATPase swap three sodium ions out for two potassium ions in, using energy. This pump sets the stage for electrical activity.
• Channels and transporters: Specialized proteins open or close to let certain ions pass at the right moment.

What Electrolytes Do

1. Run nerves and muscles:
   Nerve cells fire when sodium rushes in and potassium flows out. Muscle cells use the same principle. Calcium then triggers the contract slide inside muscle fibers. Without the right amounts, signals slow or misfire.
2. Balance fluid and blood pressure:
   Sodium is the main controller of fluid outside cells. When sodium in blood rises, water follows, which raises blood volume and pressure. Hormones such as aldosterone and antidiuretic hormone adjust kidney reabsorption of sodium and water to keep pressure and osmolality steady.
3. Keep acid base in range:
   Bicarbonate buffers acids. The lungs remove carbon dioxide to control acidity quickly. The kidneys reabsorb bicarbonate, excrete hydrogen ions, and fine tune phosphate and ammonia buffers for slower, long term control.
4. Enable enzymes and metabolism:
   Magnesium stabilizes ATP, the cell’s energy currency. Potassium helps enzymes that manage carbohydrate and protein metabolism. Chloride helps form stomach acid for digestion. Calcium is vital for signaling inside cells.
5. Move nutrients:
   Sodium glucose cotransporters in the gut pull glucose and sodium into the bloodstream together, with water following. The same logic powers many nutrient and water movements.

How the Body Keeps Balance

• Intake and absorption: The small intestine absorbs most electrolytes. Vitamin D supports calcium and magnesium absorption. Diarrhea or vomiting can rapidly deplete sodium, potassium, and bicarbonate.
• Kidney regulation: Kidneys filter blood, then reabsorb or excrete ions to match needs. Aldosterone increases sodium reabsorption and potassium excretion. Antidiuretic hormone increases water reabsorption. Parathyroid hormone increases calcium reabsorption.
• Sweat and heat: Sweat contains mostly sodium and chloride, with smaller amounts of potassium and magnesium. With heat acclimation, sweat becomes more dilute in sodium, which helps conserve it.

When Levels Drift

• Low sodium (hyponatremia): Headache, confusion, nausea, seizures in severe cases. Common risks include overdrinking water during long events or losses from illness.
• High sodium (hypernatremia): Thirst, weakness, sometimes confusion, often from water loss that is not replaced.
• Low potassium (hypokalemia): Muscle weakness or cramps, heart rhythm changes, often from diuretics or GI losses.
• High potassium (hyperkalemia): Dangerous rhythm problems, often related to kidney issues or certain drugs.
• Low calcium or magnesium: Tingling, cramps, spasms, arrhythmias in severe cases.
  Any of these require medical evaluation, especially with heart or neurologic symptoms.

Practical Takeaways

• Most people meet electrolyte needs with normal food and salting to taste. Whole foods provide a broad mix: meats and dairy for sodium, calcium, and phosphate, fruits and vegetables for potassium and magnesium.
• During long, hot, or high sweat activities, replace both water and electrolytes. Shots of plain water alone can dilute sodium if intake is extreme. Balanced fluids or salty foods help maintain osmolality.
• With stomach bugs, oral rehydration works well since sodium, glucose, and water absorb together in the small intestine. Small, frequent sips are usually better tolerated.
• People with kidney disease, heart failure, high blood pressure, or on diuretics need personalized guidance from a clinician since electrolyte handling changes.

Bottom Line

Electrolytes are the body’s wiring and water managers. They create the voltage for nerves, unlock muscle contraction, steer fluid shifts, stabilize pH, and enable nutrient transport. Your kidneys, hormones, lungs, and gut coordinate them through a continuous feedback loop so that cells stay charged, fueled, and in balance.