The human body: What are electrolytes?

We need these tiny ions to keep our muscles and nerves moving

Our bodies are huge biochemical batteries, and to keep our nerves firing, our muscles moving and our hearts beating, we need to maintain the right balance of ions, which are called electrolytes. Some of the most important are sodium (Na+), potassium (K+), calcium (Ca2+), chloride (Cl-), and bicarbonate (HCO3-).

Sodium and potassium are involved in a pump system that maintains an electrical potential across the walls of your nerves and muscles. When nerves fire, gates open and the ions rush through, triggering an electrical impulse. Negatively charged chloride ions balance sodium and potassium — calcium is involved in muscle contraction and triggering the release of chemical messages from the end of nerves, and bicarbonate works as a pH buffer, helping to keep the acidity of your body in check.

When you sweat you don’t just lose water — you lose these crucial electrolytes too. And if you only drink pure water when you’re done exercising, you aren’t replacing them. You can regain lost electrolytes from your food, but elite athletes sometimes benefit from sports drinks with added minerals to help them recharge on the go.


This article was originally published in How It Works issue 104, written by Laura Mears  


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