One of the biggest breakthroughs to come out of Kona research was describing exercise-associated hyponatremia, an electrolyte condition that occurs when athletes take in too much fluid and dilute the sodium content in the blood. Those suffering from hyponatremia would typically gain weight as a result of all the body’s retained water. Dr. Doug Hiller spearheaded one of the first studies on the condition in the ’80s. During a race early in his triathlon career, he wound up in his own emergency room at the Pennsylvania Hospital, where he was working as a medical student at the time.
“At that point I realized there were limits to human performance,” Hiller said.
He did the Hawaii Ironman from 1982 to 1984 and became intrigued by the physiology of the sport. While doing a fellowship at the University of Pennsylvania’s NASA lab, he had the freedom to research outside of his required projects and chose to look into ultra-endurance exercise, defined as activity lasting longer than four hours.
“I asked a medical student who was helping me to find every paper written on it,” Hiller said. “He found all one of them.”
It was a walking study. The conclusion was that you couldn’t walk for more than eight hours with your heart rate above 135. “It seemed everyone back then knew that you couldn’t exercise for more than three hours at a time because you’d run out of glycogen,” Hiller said. “But I had just seen Dave Scott run a sub-three-hour marathon after riding his bike as fast as he could for five hours, so I knew that was hogwash.”
Recognizing the huge opportunity for research, Hiller recruited some of the top physicians at University of Pennsylvania Medical School as well as an unknown 19-year-old by the name of Ken Glah to use as a test subject. (Glah would go on to record 26 consecutive finishes in Hawaii and place 10 times in the top 10 throughout his career.) The “Labman” team, as they became known, consisted of Hiller, Laird, Pam Douglas, Mary O’ Toole, Japanese doctors Hisao Iwane and Toshihito Katsumura and, for a short period of time, Ferdy Massamino.
Together they performed studies at races around the country, using a donated 38-foot Winnebago rolling research laboratory.
As the self-proclaimed Tom Sawyer of the Labman group, Hiller “got stuck” with electrolytes for his first Kona study in 1984.
“Everybody ‘knew’ that electrolytes didn’t change because the body knows how to adapt properly,” Hiller said.
The team drew blood from 72 athletes in Kona and compared pre- and post-race electrolytes. Not surprisingly, everyone was normal before the race, but after the race many of them were hyponatremic, or sodium-depleted. Up until that point hyponatremia was more of an issue for slower athletes who tended to overhydrate. But the athletes in the study were not only hyponatremic—they were also dehydrated.
“It blew my mind because I couldn’t find anything about that in medical literature,” Hiller said. “I didn’t even want to publish it because I was kind of afraid there was something I didn’t understand.”
He did later publish it and presented it at the American College of Sports Medicine (ACSM). The head of physiology at a major medical school dismissed the study, claiming the lab had obviously made a mistake. Despite the initial pushback—and a generation of debate to follow—this particular study was the first to report exercise-associated hyponatremia in triathletes. It immediately changed the treatment of those with symptoms.
“No one had ever done a study that affected the IV fluids we gave people in the tent,” Hiller said. “Before we came out with this study in 1985, they used half-normal saline, which is water with half as much salt in it as you have in your body. For all the long-distance races we immediately changed to normal saline with sugar in it. In fact, [if you] give somebody half-normal saline who is hyponatremic, especially overhydrated, you could end up with a really serious problem.”
Laird instituted pre- and post-race weighing to quickly identify dramatic weight changes, and now athletes at all Ironman events are weighed before they compete. In the first few years of Ironman, officials pulled athletes off the course if they lost more than 5 percent of their body weight at periodic checkpoints. Nowadays a 5 percent loss just means you’re a candidate for an IV. If you’ve gained weight, that’s an obvious sign of hyponatremia, which needs immediate and serious attention. One young English pro wound up in a coma for four days in 1984 before eventually recovering. At the world championship last October, an athlete misjudged fluid intake and gained eight pounds during the race.
“When he came into the medical tent he was lucid and tired,” Laird said. “We could immediately tell there was a problem when he stepped on the scale, so we got electrolytes in him and treated him really quickly. He still ended up in the ICU at the hospital overnight.”
One of the most famous cases of an athlete who tended to get hyponatremia was six-time Ironman world champion Mark Allen. Allen had just won the first short-course ITU World Championship in 1989 when he met Hiller, the head ITU doctor for the U.S. at the time. At that point, Allen had had success at many races but hadn’t yet cracked the code on Ironman Hawaii. Hiller invited Allen to come to the sports research lab at Duke University, where he was doing his sports fellowship.
“We had suspected that he was hyponatremic from the blood work we’d done on him [after the race] in 1984,” Hiller said. “He said he really wanted to go to our lab before competing that October.”
At the lab, Allen swam for an hour then rode a stationary trainer for six hours in an environmental chamber set at 100 degrees F and 50 percent humidity. The trainer sat inside a children’s pool that collected all of his sweat.
“If you can imagine, it’s like a big microwave oven that can only fit a guy and his bicycle,” Hiller said. “I think he said, ‘Stick a fork in me when I’m done.’”
After his ride, Allen ran on a treadmill in the chamber at six-minute miles for an hour. It started smoking. They hauled in another treadmill and he ran for another hour. That treadmill also started smoking.
Afterward they analyzed his sweat from the Kona-like conditions.
“It turned out he was losing a huge amount of sodium,” Hiller said. “We calculated how much salt he needed to take in for Ironman and recommended a product—maybe one of the first gels—that had a lot of sodium.”
The recommendation came just in time for the epic Iron War of 1989, when he ran shoulder to shoulder with Dave Scott before passing him in the final miles to win his first Ironman World Championship.