Electrolyte Replacement in Endurance Athletes

By Cintia Reis, nutritionist

Athletes and fitness enthusiasts already know that good hydration is associated with a good sports performance and preventing possible physiological disorders.  The loss of electrolytes, known as minerals occur by excessive sweating in prolonged activities, under intense heat or insufficient fluid intake.

The main electrolytes are sodium, potassium, chloride and magnesium.

The low concentration of sodium can lead to hyponatremia (marked reduction of sodium in blood) which brings as a consequence nausea, vomiting, headache and dizziness.  It is an essential mineral for glucose uptake and transport of various substances from the gut.  Sodium is not produce by the body and is absorbed through food.

Potassium is another key electrolyte to transport oxygen, regulates blood pressure, aids in mucle contraction, among others.  We find this mineral mainly in fruits.

Another important electrolyte is chloride, without it, the body is unable to keep the blood within the blood vessels, leads nerve transmissions, contracts and relaxes the muscles, and aids in the proper functioning of the liver.

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Magnesium has a special function, it assists in the absorption of other electrolytes such as potassium, and secretory action of toxins.

Lack of replacement of these substances can cause a dehydrating framework and disability, bringing irritability in the nerve endings, resulting in spontaneous contractions: cramps. Athletes must ingest the liquid at regular intervals before, during and after exercise in order to consume a rate sufficient to replace any water lost through sweat.

In prolonged exercise, for example, 10 miles (16 km), half marathon, marathon or Triathlon, carbohydrate intake helps maintain blood glucose and the preservation of muscle glycogen. The strategy used most during these exercises is  the use of solutions containing water, electrolytes and carbohydrates.

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Sodium is the most critical electrolyte to the performance and health of the athlete. In intense and prolonged activity, it is recommended to drink liquid, containing 0.5 to 0.7g/L sodium, which corresponds to a similar or even lower concentration that of sweat an adult. Supplementation through salt or electrolyte replenishing capsules is a quick and convenient way to replenish electrolyte losses. Another important recommendation for athletes is to have a diet rich in foods containing these minerals such as fruits and vegetables.

Important to remember that a consultation with the nutritionist to adopt the best strategy is recommended, respecting the intensity of training and individual dependence on electrolytes involved planning an efficient hydration focused on performance and mainly targeting the health and well-being.


Cintia Reis, nutritionist expert in sports nutrition and triathlete. Questions about nutrition? Contact: cintiabrguimaraes@hotmail.com

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