Articles

Electrolytes: An Explanation

Posted: May 29, 2012

by coach Amy Anderson

Summer has arrived, which means that it's time to chat about electrolytes.  Chemically, sodium is a "salt" but it's not the only "salt"; so are potassium, magnesium, calcium and others.   Collectively they are called "electrolytes" because they are charged ions, some positive, some negative. As they relate to marathon training, electrolytes serve two important functions:

1.  Your body uses electrical signals to stimulate nerve impulses and muscle contractions.  When your electrolytes are out of balance, you may experience muscle "misfires" and/or muscle cramps, particularly in your calves or quads.

2. You might remember "osmosis" from chemistry class. For fluids to cross cell membranes, they have to be the right osmolarity or "saltiness".  If your electrolytes are out of balance, your stomach may not absorb the water you're drinking; you'll hear and feel it sloshing around.  Or you may  pee it straight out, without it properly hydrating you.

How and why might your electrolytes become out of balance?  The most common ways are:
A) eating too much processed food, which tends to be very high in sodium and very low in other necessary salts.  Be sure you're eating enough fruits, vegetables and other non-processed foods that naturally provide you with potassium, magnesium, calcium and more.  

B) heavy sweating during hot weather exercise.

If you've experienced muscle cramps, sloshy stomach, or a layer of fine white dust on your skin and running clothes after your workouts, you may wish to consider increasing your electrolytes through supplements.  Some popular brands are Nuun, Metasalt, Salt Stick, Endurolytes and many others.  They all vary in formula and dosage, so experiment with them (and eat more fruits & vegetables!) to see what works for you.