Record temperatures bring disturbing news reports of heat-related deaths and the familiar calls to seek shade, limit outside work and drink large quantities of water.
But experts caution that water alone may not be sufficient and, in fact, could actually increase your risk of severe heat-related injuries.
According to Dr. David McCarron, adjunct professor at University of California Davis, "You must also replace the sodium and potassium along with the water. This is why athletes drink sports drinks, rather than just water. Replacing water without sufficient sodium can quickly produce hyponatremia, a potentially fatal condition."
When the body loses electrolytes, typically from perspiration, over-rehydration with only water will produce hyponatremia, which is a true medical emergency.
Hyponatremia symptoms are similar to those of heat exhaustion and heat stroke, and can often be overlooked. Symptoms range from mild to severe, and can include nausea, muscle cramps, disorientation, confusion, seizures, coma and death.
To avoid this condition, medical authorities advise marathon runners to consume extra salt, and this advice should also be considered by those exposed to excessive heat. Salt is critical in maintaining hydration.
The proper balance of electrolytes in the human body is essential for normal function of the cells and organs. Electrolytes help to regulate cardiovascular and neurological functions, fluid balance and oxygen delivery.
In 2007, a 28-year-old mother of three died from hyponatremia hours after competing in a radio-station contest to see which contestant could drink the most water without urinating.
A few years ago, a 21-year-old student died of water intoxication during a hazing incident. He had been forced to drink from a five-gallon jug of water that was repeatedly refilled. He soon collapsed.
Fraternity members didn't initially call an ambulance. By the time they did, it was too late. He was pronounced dead a few hours later.
Elderly Also at Risk
Water intoxication is more commonly seen among athletes, usually extreme athletes, but older individuals are also at high risk for several reasons. Their kidneys are less efficient at conserving salt when the body is stressed, and common medications such as diuretics greatly increase that risk.
That is why during severe high temperatures, news accounts most often refer to elderly victims of the heat.
Although most hyponatremia victims may not have obvious symptoms, severe hyponatremia is a medical emergency that calls for immediate treatment. The low sodium level is restored to a normal level by gradually and steadily giving sodium and water intravenously. Milder cases can be handled by administering of salt and fluid replacers by mouth.
The next time the local meteorologist recommends cranking up the air conditioner and drinking a lot of water to beat the heat, remember that doctors also recommend cranking up your intake of electrolytes, particularly sodium and potassium.