Summer heat can leave our bodies hanging in the balance.

Too much water, we die. Too little water, we die. Too much salt in that water, we die. Too little, we die. Too much potassium... you know the rest.

Our bodies are two-thirds water, with a mix of minerals floating around and a salt content similar to the ocean. Somehow our cells get bathed, drained, fed and filtered with this liquid soup. But what sparks this concoction of water and minerals in our cells so that we breathe, think and move?

Electrolytes (ee-LEK-troh-lites) regulate the performance of our organs and life functions. These substances are minerals, such as salt, that break into particles and when dissolved, become electrically charged. These charged particles—or ions—are required by our cells to regulate the flow of water across the cell membrane and conduct currents between cells in the blood. Their basic functions are to send messages to every cell in the body and manage nutrients and eliminate waste in every cell in the body.

This strange brew circulates through us to trigger impulses in our cells for all sorts of body functions from blood clotting to heart beat and everything in between.

Although a multitude of substances constitute the electrolytes in our bodies, the most abundant are sodium, potassium, calcium and magnesium, those same chemicals from the Periodic Table. Other common electrolytes are chloride, phosphate and carbonate. These can be measured with a simple blood test, usually part of your annual physical.

“We’ve evolved over time so that our electrolytes can withstand fluctuations and still operate efficiently within a range, beyond which we get sick,” says Michael Altman, MD, assistant professor in the Department of Family Practice and Community Medicine at The University of Texas Medical School at Houston. Outside the healthy range—electrolyte abnormalities—we experience heart failure, seizures or a range of other health problems.

Electrolyte abnormalities can be asymptomatic or dramatic. When sodium or potassium levels are too high or too low, your body can respond drastically. Your heart might beat out of rhythm, muscles may become paralyzed. You may lose consciousness, become delirious, go into coma.

Dehydration

When you exercise in the heat, you’re more likely to face dehydration, water and minerals lost through sweat and an increased salt concentration.

When your body sweats, it not only is purged of water, but also salt, potassium and other electrolytes.

Problems can arise when physical exertion forces electrolytes to function in spite of imbalances. People with impaired organ function, such as the sick or elderly may experience electrolyte imbalances. The thirst sensation wanes with age and dehydration can occur. Changes in hormone levels can also lead to electrolyte imbalances.

Dehydration also can occur from an acute bout of vomiting and diarrhea. Children and the elderly are especially prone to dangerous dehydration and a call to a health care provider is in order if there are symptoms of dehydration.

With dehydration, your warning signs would be thirst, exhaustion, profuse sweating, darkened (concentrated urine) and then an absence of sweat altogether. In extreme cases, poor skin turgor (skin that does not bounce back when pinched or pressed), fever over 104 degrees, loss of consciousness or seizure all signal a need to seek immediate emergency care.

“Electrolyte disturbances are especially troublesome when a person's water balance is subjected to high humidity, external heat, and increased core body temperatures from exercising muscles—conditions well known to people in the Sun Belt,” Altman says.

You might then over-compensate, drink too much water at once, and have problems with water intoxication. When your body doesn’t have enough salt, you might feel fatigue or get a headache.

Powerful potassium

Potassium is essential to maintaining normal muscle function. Low potassium can lead to severe cramping or muscle weakness. So, imagine how essential potassium is to the body’s most important muscle: the heart. Potassium fluctuations can knock a heart dangerously out of rhythm, which is what happened to then 49-year-old fitness trainer, Paula Feinman.

Four years ago, Feinman noticed the odd, feathery feeling of irregular heart beats. “Then, I would have these sharp, chest pains that ran straight through from front to back,” she recalls.

One afternoon, long past her workout, the chest pains and arrhythmias grew severe; she felt faint and her left arm began to ache.

After a trip to the emergency room by ambulance, her cardiologist diagnosed her with a life-threatening potassium deficit. “Between the amount of fluid I lose in sweat, a low-dose diuretic, my own unique biochemistry and a rare few (alcoholic) drinks the night before at a party, I must have hit the tipping point,” Feinman says. She was prescribed a daily potassium supplement and is still monitored regularly.

Too much water

Electrolyte imbalances can be dramatic enough to land victims in the headlines. In early 2007, a California radio station staged a competition to see how much water participants could drink without a bathroom break. What seemed like a harmless contest left a woman dead from water intoxication. The 28-year-old mother of three ignored her impulse to urinate after reportedly drinking up to two gallons of water. She then developed a severe headache.

The headache was a signal that the abundance of water in cells throughout her body had diluted the sodium concentration in her blood to a fatally-low level. Her kidneys, which under normal conditions would be able to regulate the amount of sodium and water, could not eliminate the excess water into the urine fast enough to reconcile the imbalance.

Even though water intoxication, known as hyponatremia, is not a condition you would normally encounter, endurance athletes or others performing strenuous tasks might occasionally have a problem with salt imbalance, whether it be too little or too much.

“Permanent damage due to abnormal salt concentration in the blood may be caused when cells shrink or rupture,” Altman explains.

Supplements and Medication

Sports drinks contain electrolytes and carbohydrates. They do help with rapid replacement of water and sodium, the deficits that occur with common, prolonged exercise.

“If you are in good health and eat a healthy diet, you shouldn’t need to take supplements unless directed by a doctor. Sports drinks have the benefits of glucose, and they make water consumption more palatable, but they have not been shown to help balance electrolytes,” Altman says.

Since potassium is so critical to cardiac function, medications that act as diuretics (“water pills”) often have a “potassium-sparing” feature so that you don’t lose this essential chemical through the urine. Your physician also may prescribe potassium supplements when taking certain medications.

Potassium supplements however are to be taken only under medical supervision and by prescription. Too much potassium is as dangerous as too little. Foods naturally rich in potassium are bananas, oranges and potatoes, to name a few.

Diabetes can also cause disturbances in electrolytes, although this is generally a problem with poorly controlled diabetes. “In juvenile diabetes, there can be massive fluid shifts and diabetic ketoacidosis (insulin deficiency). Today, there is good treatment, and these conditions are not critical if managed properly,” Altman says.

While controlling electrolytes is not as easy as counting calories, you can rely on your own awareness of your body under physical stress, your yearly physical and blood test results, and guidance from your physician if you have conditions that might provoke imbalances.

 

UPDATED: 7-02-2008

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