Most of us, but especially runners and other cardio bunnies, have heard of the need to replace electrolytes lost through sweat. But why?

Sodium is one of the most abundant elements of earth, found accessibly for human consumption in salt (sodium chloride) and is one of the body’s 3 major electrolytes (potassium and chloride are the other 2). Electrolytes control the fluids going in and out of the body’s  tissues and cells. Salt, which contains both sodium and chloride, is a major source of electrolytes. When the body becomes dehydrated, it loses fluids and electrolytes, but taking in fluids without sodium doesn’t always hit the spot for re-hydration during exercise.

The movement of sodium in and out of the body also allows the body to engage in muscle contraction and nerve signaling and is vital for the maintenance of of blood volume. Heavy or ‘salty’ sweaters can lose large amounts of salt during exercise through their sweat. By the time an athlete feels thirsty, they have usually lost 2% of their body weight through fluid loss.
When dehydrates, the body loses its ability to control temperature, which can result in an elevated heart rate, muscle cramping and reduced muscle power.
Sodium levels in the blood is the body’s main stimulus for thirst and so sodium consumption during exercise maintains the physiological drive to drink and can reduce or prevent dehydration when taken with appropriate fluid volumes.

For a healthy, cheap and natural electrolytes replenishing drink, try this: https://www.earthclinic.com/remedies/how-to-make-homemade-electrolyte-drink.html

Sodium Facts (220 Triathlon Guide to Nutrition, 2013)