No, they’re not just something invented by Gatorade.

Electrolytes occur naturally in human beings and play a crucial role in our bodies’ function. Athletes working at long duration or high intensity — including CrossFitters — should be familiar with what electrolytes are and how to replenish them after a workout.

So what exactly are they and how do they work?

Electrolytes are types of salt. Without getting too scientific, electrolytes are electrically charged ions that are found in body fluids, including blood, plasma, and the fluid between our cells. Because they carry a positive or negative charge, they help transfer electrical impulses throughout our bodies. This is important for proper function of our muscles and nerve fibers. They also regulate our bodies’ voltage.

When we exercise heavily, we lose electrolytes through sweat. Sick people can also lose electrolytes through severe vomiting or diarrhea. Although our kidneys work to keep electrolytes in our blood, sometimes we need to supplement them externally.

“In addition to repletion with water, athletes must make sure they are repleting their electrolyte stores adequately,” said CFCOA endurance coach Anthony Madonna.

Water alone won’t address electrolyte loss. Low levels of electrolytes can most commonly result in fatigue and muscle twitching. In severe instances, people can experience irregular heartbeat, confusion, and blood pressure changes.

So how do you know if you’re low? If you’ve just worked out and your shirt is sopping wet with sweat, you’re almost certainly in need of more electrolytes.

“Consume enough electrolytes, balanced with proper amounts of water,” Madonna said. “You want approximately 250 calories per hour for an average-sized person, and enough water to hydrate but not over-hydrate.”

Electrolytes are found in a variety of beverages. CFCOA offers two recovery drinks in the store: Vita Coco, a natural offering of coconut water, and Kill Cliff, an engineered drink that also includes vitamins and micronutrients. If you’re shopping on your own, you might look for a recovery drink that also includes branch chain amino acids (BCAAs) for better muscle building and recovery. But that’s a different blog post…