Wary of too much water: Risk of overhydration is often overlooked as heat-related hazard

Monday, July 15, 2002 | 11:08 a.m.

They say too much of a good thing can kill you.

However, many Las Vegans, sweltering under blistering desert skies and drinking lots of water to remain hydrated, would argue that certainly the "too much of a good thing" rule cannot possibly apply to good ol' H20.

Guess again.

Military doctors are rethinking -- and have issued new guidelines for -- limits on water consumption in the wake of three deaths in an 18-month period of recruits who, officials say, succumbed from drinking too much water.

While such deaths are rare, new concerns are being raised regarding water consumption, especially when so many people, especially those who toil under sunny skies, have never even heard of water toxicity.

"There is a much, much greater risk of becoming dehydrated than overhydrated," said Maj. Steven Ross, an emergency room physician at Nellis' O'Callaghan Federal Hospital. "Still, we have guidelines for overhydration.

"In my (eight-year) career, I have treated two overhydration cases. Both of them survived. The best prevention is moderate your water intake."

Water toxicity can occur when the body cannot sweat out a large intake of liquid fast enough, causing the water to go to the bowels, taking salt with it from the tissues. Such a loss of sodium concentration combined with drinking even more water can cause the brain to swell and become damaged.

The Office of the Armed Forces Medical Examiner in Rockville, Md., reported that between September 1999 and March of last year, three recruits in training died from hyponatremia, or acute water intoxication. In July 1997 the first such death was recorded, of an Army recruit at Fort Benning, Ga.

The 1999 death involved a 19-year-old Air Force recruit who collapsed during a 5.8-mile walk at Lackland Air Force Base in San Antonio. His body temperature had climbed to 108 degrees and his sodium levels were low from overhydration.

A March 2001 death of a Marine at Camp Pendelton, Calif., came after he got ill during a 26-mile hike, and a January 2000 death of an Army woman at Fort Jackson, S.C., occurred after she drank three gallons of water trying to produce a urine specimen.

"Most of us can't drink so much water -- we simply get full and stop," said Dr. Larry Allen, a Las Vegas internal medicine specialist, who noted those deaths came from extreme circumstances. Other factors can contribute to hyponatremia, like taking diuretics or consuming too much alcohol, he said.

Col. John Gardner of the Armed Forces Institute of Pathology in Virginia, the author of the report, said it is important to replace fluids, because the average person loses two quarts a day.

"We've always stressed to drink a lot of water ahead of thirst because if you are thirsty you already are a pint low," Gardner said. "In the last 10 years, however, we have found that water consumption has been taken to the extreme."

In October 2000 the branches of the military issued new water consumption guidelines for training in hot environments, warning: "ingestion of large amounts of water -- greater than 1 1/2 quarts per hour -- may lead to hyponatremia, which is a life-threatening condition."

The most significant change limits water intake to about one quart per hour. The old standard was two quarts.

The military, however, left its maximum daily recommendation at three gallons.

Allen recommends 10 glasses a day -- just under a gallon -- for a moderately active person.

Ross said diagnosing overhydration becomes a little tricky, because the symptoms for overhydration and deyhdration are similar -- dizziness, profound fatigue, vomiting, confusion and seizures. In either case, he said, get out of the sun and seek immediate medical attention.

To determine whether a patient is dehydrated or overhydrated, Ross said, a sodium test is done. A overhydrated person will have a low level, while a dehydrated person will have a high one.

While some of the military deaths occurred in desert climates, "humid climates are much worse" for increasing the risk of death by overhydration, Gardner said.

In the desert, sweat evaporates quickly, thus releasing body heat, he said. People in humid areas find themselves dripping with sweat which, unlike evaporation, does not take away body heat. Thus it is more likely people in humid regions could consume too much water quickly to try to cool down.

Las Vegans who engage in outdoor activities were surprised to learn that it is possible to drink too much water and get sick or die.

"That's news to me," said Danny Ulloa, organizer for Roofers Local 162, which represents 300 union roofers in Las Vegas. "I've worked on roofs where the temperature was 120-130 degrees. I've always drank plenty of water."

Nellis Air Force Base airmen working outdoors drink plenty of water as well.

Civil engineer airmen repairing sections of concrete on the Nellis flight line in the midday sun say it is not uncommon for them to drink every drop of their three-gallon daily limit.

One airman, sipping on water through a tube from a backpack-like device that holds up to 100 ounces, said he goes through several refills, yet sweats so much he urinates only once a day.

But airmen also have the benefit of technology. They are monitored by a device that determines how long they should work in the heat, at what exertion level and when they should consume liquids, Ross said.

High school football teams, which begin daytime football workouts in mid-August, rely on common sense guidelines, Mike Gutowski, football coach at Mohave High School and the president of the Southern Nevada AAAA Football Coaches Association, said.

"We take water breaks every 40 to 45 minutes," he said. "The kids don't guzzle the water, because if they did they'd feel bloated and get sick."

Gutowski said that while he had never heard of water toxicity, trainers are present and coaches are trained in cardio-pulmonary resuscitation and could respond to a problem.