Anyone who has ever picked up a bottle of Gatorade or coconut water knows that one of the selling points for these beverages is their electrolyte contents. But even if you know that electrolyte content is good for your body, you might not know exactly why they’re good for you. And even if you have a general idea of the role electrolytes play in your body’s function, you might not necessarily have a good understanding of the science behind it. All of that being said, we decided to do a bit of a deeper dive.
By definition – and in the context of nutrition, specifically – electrolytes are compounds that produce ions when dissolved in water. In other words, they are the electrically-charged versions of a few different minerals that are dissolved in your body’s fluids. More specifically, these minerals are sodium, potassium, calcium, and magnesium.
One function of electrolytes is balancing the pH of your blood, making sure it never becomes too acidic or too alkaline. Additionally, sodium and potassium help to balance the fluid in your cells so that they don’t become dehydrated or burst with overhydration, while calcium and magnesium help to stimulate contractions in muscles such as the heart.
When you sweat excessively, whether it’s from heat, exercise, or both, you lose different quantities of each of these. While every person is unique, on average a person loses about 900mg of sodium, 200mg of potassium, 15mg of calcium and 13mg of magnesium per liter of sweat. This means that when you drink water to replace moisture lost through sweat, you also need to replace electrolytes, as water alone will dilute the minerals further and can be dangerous.
This is where we can consider those electrolyte-replacing energy drinks. A liter of Gatorade contains less than 500mg of sodium, which is half (or less) of what you would typically lose in a liter of sweat. Coconut water contains even less. Your best option for replacing electrolytes when you are sweating heavily for long periods of time (i.e. running a marathon) is consuming salty foods or salt pills paired with water replacement. For example, a small bag of pretzels contains roughly the equivalent of sodium lost in one liter of sweat, as well as some other electrolytes. If you are sweating heavily for long period of time, you should try to replace the fluid and electrolytes you lose at least once per hour.