What are electrolytes?

After a long, hard run someone is bound to remind you about the need to replenish your electrolytes, lest you shrivel up. They’ll tell you to eat a bananna. Someone might say something about dehydration and potassium.

Electrolytes can be a confusing topic. Why doesn’t water always cut it? And when is only water fine?

Electrolytes are ionic minerals and carry a positive or negative charge. They play an important role in your body because they are what causes your cells to carry charges between themselves and communicate, allowing muscle function. They also manage blood acidity and pressure. Without these electrolytes your body starts shutting down, and you lose them in a variety of ways. You need them for muscle contraction and relaxation, meaning you need them to keep moving.

Generally, when talking about athletic performance and electrolytes people are referring to sodium, potassium and chloride. There are others which play important roles in the body, but in terms of keeping hydrated and running these three are the ones usually discussed. Sodium attracts water, moving it around the body, and helps keep the balance of water between cells consistent.

The substances you need to stay hydrated are found naturally in most fruit juices and milk. Bananas are packed full of potassium, making them a great post-workout snack. These electrolytes are also the basis for the invention of the sports drink. Gatorade and Powerade built their brands on replenishing the electrolytes lost during exercise.

When you sweat you lose electrolytes, so exercising for extended periods of time without replenishing them can have nasty repercussions later. There are other, less stomachable ways to lose them, also. The stomach flu, because of vomiting, can cause serious dehydration, and anyone who has been very dehydrated can attest it is not an enjoyable feeling.

Generally a healthy diet will keep your electrolyte levels fine. North American diets, full of table salt, mean we are rarely at  a shortage for sodium, and eating lots of fruit and vegetables keeps potassium levels high. Usually water is all someone needs to keep hydrated, but in bouts of exercise lasting longer than an hour, such as running a half-marathon or more, replenishing theses salts is vital to performing well, and in some cases finishing.