Electrolytes, like sodium, potassium, calcium and magnesium, are electrically charged particles which, when dissolved in water, produce charged ions. These ions permit the flow of electrical signals throughout the body. Electrolytes own many roles, such as helping to maintain fluid balance, heart rhythm and the functioning of muscle and nerve cells.
As a consequence of sweating, you lose water and electrolytes. In certain situations, such as in endurance events, high-intensity exercise and training or racing in a hot environment, extreme sweat losses can sabotage performance and health due to excessive electrolyte and fluid imbalances.
Electrolyte and fluid imbalance symptoms include dizziness, muscle weakness, decreased urine output, dark urine, fatigue, nausea, irregular heartbeat, dry mouth, breathing difficulties, stiff joints and dry skin. Although a standard sweat test can help you determine fluid losses, it can be challenging to determine your personalized electrolyte needs. To ensure that you get enough, but not too much, of electrolytes, follow these guidelines:
5K (up to 45 minutes): No sport drink necessary. Go into the race hydrated and fueled.
10K (up to 90 minutes): A sport drink “mouth rinse” (swish and spit) may boost reward centers in the brain. Otherwise, water is recommended, electrolytes not required. Be sure to go into the race well-hydrated and fueled.
Half marathon and marathon (3+ hours): A sport drink or gel/energy chew + water combo. For every 20 minutes of running aim for:
100–250 mg sodium
8 oz fluid
10 g carbohydrates
Take a sip/swig of your sport nutrition product every 10–15 minutes.