In a sport that has seen surprisingly few changes in its training and preparation philosophies over the last couple of generations, recent warnings over the presumed dangers of a condition known as hyponatremia have been met with alarm throughout the marathon world.

However, physicians and race directors in Hawai'i say the response by some race organizations has been disproportionate to the threat, and may in fact place runners in greater danger.

Hyponatremia is a serious sodium imbalance that can be caused by excessive fluid consumption. Much of what is known or presumed about the condition comes from a 1985 paper authored by South African marathoner and sports-medicine physician Tim Noakes.

Noakes linked hyponatremia to the proclivity of endurance athletes to consume large amounts of fluid during events to prevent dehydration.

Noakes' work received little attention at the time, and physicians and the running community largely regarded hyponatremia as a medical curiosity rather than a serious threat.

Dr. Jack Scaff, one of the founders of the Honolulu Marathon and a Honolulu physician who has lectured on hydration, heat-related illness and other medical issues associated with endurance athletes, said Noakes' research was fundamentally flawed and potentially reckless in its assumptions.

"(Noakes) has refused to admit that heatstroke exists," Scaff noted. "If you're not willing to admit that it exists, you're never going to see it, and then a myth develops around what we call a 'fixed false belief.' "

Such a stance would compromise the interpretation of results, Scaff said, particularly since the two conditions have similarities in cause and development.

The issue finally gained widespread attention after the 2003 deaths of 28-year-old Cynthia Lucero at the Boston Marathon and 35-year-old Hilary Bellamy at the Marine Corps Marathon were attributed to hyponatremia.

In the aftermath, Noakes' work was frequently cited in articles published in medical journals, popular magazines and major newspapers. As alarmist headlines like "Don't Drink the Water" (The New York Times) and "Too Much of a Good Thing" (The Washington Post) fueled the fire, several running associations adopted policies and recommendations aimed at discouraging runners from drinking too much. The Houston Marathon, for example, reduced its aid stations from 26 to 13.

Such actions seem to reflect Noakes' assertion that hyponatremia poses a more serious and prevalent threat to the health of endurance athletes than dehydration.

"I don't buy into it," said Dr. Jim Barahal, president of the Honolulu Marathon Association. "Based on our experience, it seems rabidly counterintuitive."

Scaff and Barahal contend that the probability of a runner getting hyponatremic is minimal compared to the risk of dehydration and heat-related illness. In a race like the Honolulu Marathon, a warm-weather event that attracts more than 20,000 runners each year, recognizing that difference is crucial.

Barahal and Scaff point to the fact that the Honolulu Marathon has provided ample water and sports drinks at its 17 aid stations and has never had a death attributed to hyponatremia or heat-related illness.

In contrast, this year's disastrous Chicago Marathon, in which overheated runners were unable to find adequate hydration and several were hospitalized for heat-related illnesses before the event was shut down, seems to support claims that heat and dehydration pose a bigger threat to marathon runners than the possibility of hyponatremia.

"In our warm, humid environment, most people are chronically dehydrated," Scaff said.

Scaff and Barahal agree that hyponatremia due to excessive fluid intake is relatively easy to prevent: Don't overhydrate before the race (it doesn't help) and be sure to take sports drink at the aid stations to replenish necessary salt and electrolytes if you're going to take longer than five or six hours to finish.

Reach Michael Tsai at mtsai@honoluluadvertiser.com.