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Fluids in your body

Athletes have been swigging electrolyte replenishers since 1965. That was the year a Florida Gators coach asked doctors why his players were wilting so quickly in the heat. Their answer? The players were losing too many electrolytes. Their solution was to invent Gatorade. So, what are electrolytes and why are they important?

Water and electrolytes are essential to your health. At birth, your body is about 75 to 80 percent water. By the time you’re an adult, the percentage of water in your body drops to approximately 60 percent if you’re male and 55 percent if you’re female. The volume of water in your body will continue to decrease as you age.

Fluid in your body contains things such as cells, proteins, glucose, and electrolytes. Electrolytes come from the food and liquids you consume. Salt, potassium, calcium, and chloride are examples of electrolytes.

Electrolytes take on a positive or negative charge when they dissolve in your body fluid. This enables them to conduct electricity and move electrical charges or signals throughout your body. These charges are crucial to many functions that keep you alive, including the operation of your brain, nerves, and muscles, and the creation of new tissue.

Each electrolyte plays a specific role in your body. The following are some of the most important electrolytes and their primary functions:


  • helps control fluids in the body, impacting blood pressure
  • necessary for muscle and nerve function


  • helps balance electrolytes
  • helps balance electrolytes
  • balances acidity and alkalinity, which helps maintain a healthy pH
  • essential to digestion


  • regulates your heart and blood pressure
  • helps balance electrolytes
  • aids in transmitting nerve impulses
  • contributes to bone health
  • necessary for muscle contraction


  • important to the production of DNA and RNA
  • contributes to nerve and muscle function
  • helps maintain heart rhythm
  • helps regulate blood glucose levels
  • enhances your immune system


  • key component of bones and teeth
  • important to the movement of nerve impulses and muscle movement
  • contributes to blood clotting


  • strengthens bones and teeth
  • helps cells produce the energy needed for tissue growth and repair


  • helps your body maintain a healthy pH
  • regulates heart function

Fluids are found inside and outside the cells of your body. The levels of these fluids should be fairly consistent. On average, about 40 percent of your body weight is from fluids inside the cells and 20 percent of your body weight is from fluids outside the cells. Electrolytes help your body juggle these values in order to maintain a healthy balance inside and outside your cells.

It’s normal for electrolyte levels to fluctuate. Sometimes, though, your electrolyte levels can become imbalanced. This can result in your body creating too many or not enough minerals or electrolytes. A number of things can cause an electrolyte imbalance, including:

The International Marathon Medical Director’s Association offers the following guidelines for maintaining good hydration and electrolyte balance during activity:

  • If your urine is clear to straw-colored before a race or workout, you’re well hydrated.
  • You should drink a sports drink containing electrolytes and carbohydrates if your sporting event or workout lasts longer than 30 minutes.
  • Drinking water with a sports drink decreases the beverage’s benefits.
  • Drink when you’re thirsty. Don’t feel you must constantly replenish fluids.
  • Although the needs of each individual differ, a general rule of thumb is to limit fluids to 4–6 ounces every 20 minutes of a race.
  • Seek immediate medical advice if you lose more than 2 percent of your body weight or if you gain weight after running.

Serious emergencies from electrolyte imbalances are rare. But it’s important to your health and, if you’re an athlete, your performance to maintain a healthy electrolyte balance.

Symptoms of electrolyte imbalance vary depending on which electrolytes are most affected. Common symptoms include:

  • nausea
  • lethargy
  • fluid retention

Electrolyte imbalances can be life-threatening. Call 911 if someone has the following symptoms:

  • confusion or sudden change in behavior
  • severe muscle weakness
  • rapid or irregular heartbeat
  • seizures
  • chest pain

Treatment is determined by the cause of the electrolyte imbalance, the severity of the imbalance, and by the type of electrolyte that’s either in short supply or overabundant. Treatment options normally include either increasing or decreasing fluid intake. Mineral supplements may be given by mouth or intravenously if depleted.