You can sure work up a sweat playing sports, especially outdoors on a hot summer day. If you're not the one grabbing a cold bottle of water off the sidelines, then you just might be reaching for your favorite sports drink to replace all those lost liquids.

But behind those flashy labels, fruit flavours and bright colours of a sport drink, there is a simple science. It is the science of electrolytes and carbohydrates.


An electrolyte is a molecule with free ions, meaning that it is an atom with a net electric positive or negative charge. Electrolytes have many functions, including helping to regulate hydration as well as nerve and muscle function. They are mostly found in the fluid within cells, the fluid surrounding cells, and in the blood.

The body loses electrolytes and water after profuse sweating so naturally, they need to be replaced. Although drinking pure water will hydrate you better than any other liquid, it doesn't restore electrolytes.

In fact, pure water can dilute the electrolytes inside the body's cells and interfere with their chemical functions. Sports drinks, like Gatorade or Powerade, however, are a combination of both water and electrolytes and can help replenish the body of both.


Did You Know?
Sweating is a body's natural way of regulating body temperature. Athletes lose electrolytes through their sweat while exercising

The three main electrolytes found in sports drinks are sodium, chloride and potassium.

Sodium, which has the chemical notation Na+, and chloride, Cl-, are two electrolytes which you are familiar with already. In fact, you don't have to look further than your kitchen table for an example of a sodium and a chloride electrolyte. That's right, table salt - sodium chloride to be exact.

And if you've ever eaten salty foods, you know how thirsty you can get. Salt controls the amount of water in the body and in a sports drink, is a great addition — it not only encourages you to drink, but helps keep those fluids in your system by preventing loss of water through urination. It's also necessary for the brain to communicate with electrical signals to the nervous system and muscles.

Potassium helps keep cells in the body functioning normally. Potassium, designated K+, has many functions in the body which include controlling the heartbeat as well as operating the muscles.


Did You Know?
Electrolytes like sodium and chloride help regulate the levels of fluids in your body


The sugars usually found in sports drinks are glucose, fructose and sucrose. Glucose and fructose are the simplest of all sugars which are known as monosaccharides ("mono" meaning one for the single sugar/saccharide unit). When two monosaccharides are mixed together they create a disaccharide ("di" meaning two sugar units). Sucrose is a disaccharide because it is glucose and fructose mixed together.

Each of these sugars are carbohydrates and are another important part of sports drinks since carbohydrates are also lost through physical activity. Carbohydrates are like fuel for your parent's car since they provide energy to your working muscles to allow you to go longer and stronger.


Did You Know?
Carbohydrates, like glucose and sucrose, are added to sports drink to provide energy

But not all carbohydrates are created equal. Sugars are simple carbohydrates meaning the body puts them right to work as soon as they are eaten — great for sports! This is because the body doesn't have to work very hard to convert the sugars into energy. This speedy use of the sugar results in a sudden release of energy. However this burst of energy goes as quickly as it came, leaving you feeling more tired than before if you don't fuel up again.

Store-bought sports drinks aren't the only solution to replacing electrolytes, carbohydrates and water. A homemade mixture can be made with the right amount of salt, water and sugar — add a little flavoring like lemon juice and voila! Instant sports drink.

So while going on a run or practicing a game of basketball, remember the science that is there to keep your performance at its best. Whether it is with a store bought or homemade sports drink, your body could use more than just water!

Learn More!

Water and Electrolyte Absorption

The Science of Carbohydrates

What's the Big Sweat About Dehydration?

Sarah Hoyles is an Associate Producer on the CBC radio program “Definitely Not the Opera”. Before joining the DNTO team in Winnipeg, Sarah freelanced with various radio stations including CBC Radio 3 as well as Edmonton’s CKUA radio and local newspapers. She graduated from the Journalism program at the University of King's College in Halifax and the University of Alberta with an Honors Arts degree in Drama.


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