Do Runners Even Need to Replace Electrolytes?

Pretty much any sports drink you can find on the market will have three main ingredients: water, sugar, and electrolytes....When we talk about “electrolytes,” we’re primarily referring to sodium ions, which make up the bulk of the non-water content of your sweat. Sodium is what makes your sweat taste salty, and it’s the primary constituent of the electrolytes lost in sweat. Some potassium is lost in sweat as well, but potassium losses are about one-tenth of sodium losses. According to traditional logic, if you’re losing electrolytes in your sweat, you need to replace them with a sports drink. Some people have even suggested that rehydrating without replacing electrolytes lost in sweat can lead to hyponatremia, a dangerous medical condition where the sodium levels in your blood are too low. But scientific research paints a different picture. Although electrolytes are indeed lost in sweat, they are at a lower concentration in sweat than in blood. So as you sweat more and become dehydrated, the sodium levels in your body rise, as the fractional losses of sodium have a concentrating effect.

posted Thursday February 22nd