Avoid dangerous over-hydration this summer

As summer sports and outdoor activities heat up, researchers at Loyola University Medical Center want to shed light on an overlooked and potentially life-threatening condition: hyponatremia, or excessive water consumption.

Last summer, there were two reported incidences of death as a result of hyponatremia. Zyrees Oliver, a 17-year-old star football player at Douglas County High School in Georgia, drank two gallons of water and two gallons of Gatorade during practice. He collapsed at home later that day and died at a hospital. Another teen football player in Mississippi, Walker Wilbanks, was taken to the hospital during the second half of a game after vomiting and complaining of a leg cramp. He had a seizure in the emergency room and later died from exercise-associated hyponatremia (EAH).

In recent years, researchers say there have also been more than a dozen documented and suspected runners' deaths from hyponatremia.

Hyponatremia is a condition that arises when athletes or others drink too much water or sports drinks. Excessive fluid consumption can overwhelm the body's ability to remove excess water, which dilutes the sodium content of your blood. Your body's water levels then rise to equalize sodium levels in your cells, which swell. The swelling can cause mild problems including muscle cramps, nausea, vomiting and seizures. If swelling occurs in your brain it can be fatal.

"It can be lethal, but essentially all deaths from exercise-associated hyponatremia are 100 percent preventable," Dr. James Winger, a sports medicine physician at Loyola University Medical Center told CBS News in an email. "We are, however, seeing hyponatremia in new settings, such as American football, paddling and long distance ocean swimming. This is supported by the common but erroneous belief that mild-to-moderate dehydration during exercise is detrimental to health or performance."

According to a July 2015 report on the Third International Exercise-Associated Hyponatremia Consensus Development Conference in Carlsbad, California, smaller individuals and those who exercise at a slower pace tend to drink more than they lose through sweat. "Although the incidence of women experiencing EAH is greater than that of men, adjusted for BMI and racing time, the apparent sex difference is not statistically significant," the report states.

To prevent hyponatremia, researchers agree that there need to be more educational programs available to athletes and coaches that stress the importance of appropriate hydration practices and provide information on how to recognize and treat hyponatremia.

The Loyola researchers advise athletes to consume water and sports drinks only when thirsty. Don't drink a predetermined amount or try to "get ahead" of thirst by drinking more than you actually want.

"The risks associated with dehydration are small," Winger said in a press release. "No one has died on sports fields from dehydration, and the adverse effects of mild dehydration are questionable. But athletes, on rare occasions, have died from overhydration."