What are electrolytes and why do sports nutrition experts recommend them for athletes? Are they some kind of super energy source? Why is a sports drink containing electrolytes any better than plain water? To best address these questions, it will be helpful have an understanding of the function of electrolytes in the human body.
When mineral salts dissolve in water they break up into electrically charged particles, or ions. These are what we refer to as electrolytes. In the human body some of the most important of these are sodium, potassium, magnesium, calcium and chloride. These electrolytes have several important functions. They are vital for maintaining fluid balance in the body. They help regulate the balance of water within and between body cells. Total body hydration and acid-base balance are dependent on proper fluid and electrolyte balance.
Other functions of electrolytes that are especially important to athletes involve nerves and muscles. Though electrolytes don’t contain energy themselves, they are essential for conducting electrical impulses used by the body’s nerves and muscles. Both nerves and muscles operate via electrical impulses activated by electrolytes in and around the cells. Muscle contractions require the presence of adequate sodium, potassium and calcium. If theses electrolytes are not available in sufficient quantities, muscle weakness or cramping may occur. Likewise, sodium, potassium and calcium are necessary for the transmission of nerve impulses which carry signals up and down the nerves directing muscle actions. If there is an electrolyte imbalance neurological functions are hindered. In some cases, the brain may be signaling the muscles to contract, but the signals are not transmitted well enough for the muscles to receive or respond to them very well, resulting in slow reflexes or weakness. In essence, it’s like trying to receive a cell phone call in an area where there are “no bars”. Electrolyte imbalance can also compromise the function of the brain itself, resulting in impaired judgment, mental confusion and fatigue. Often these symptoms can mimic those of “bonking” which occurs when the body in running out of fuel. In extreme cases of electrolyte depletion, seizures or even heart failure can occur (since the heart is a muscle whose contractions are stimulated by nerve impulses). Hence, maintaining good fluid and electrolyte balance is essential to health and athletic performance.
As athletes train and perform they lose fluids and electrolytes via sweat. Hydrating with water alone can help prevent over-heating, but won’t protect against electrolyte imbalances that can hinder performance. In some cases drinking only water can dangerously dilute out the electrolytes in the body, actually worsening electrolyte imbalances (hyponatremia). Conversely, consuming an electrolyte containing sports drink can minimize the risk of muscle cramps and fatigue by replacing electrolytes lost in sweat. Well-formulated electrolyte beverages will also enhance fluid absorption and encourage thirst, allowing for more rapid rehydration. Electrolyte replacement beverages have a clear advantage over water for promoting fluid and electrolyte balance, which in turn helps to optimize health and athletic performance.
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