Army Researchers Study Effects of High Altitude on Soldiers

By Sarah Maxwell
Special to American Forces Press Service

Sept. 16, 2008 - Looming in the distant skyline here, Pike's Peak is one of the nation's most popular tourist destinations, hosting hundreds of thousands of visitors on its 14,110-foot summit each year. What most vacationers don't know as they peer across the serene landscape is that just a few hundred feet away, researchers from the U.S. Army Research Institute of Environmental Medicine are sharing the summit to advance military medicine.

For years, research physiologists from the U.S. Army Medical Research and Materiel Command's USARIEM and research volunteers have spent their summers above the tree line to study ways of improving servicemembers' capabilities in high-altitude environments at the Maher Memorial Altitude Laboratory.

"The Army is very interested in any means to accelerate acclimatization," said USAREIM research physiologist Dr. Allen Cymerman. "We're obligated to have our troops knowledgeable and experienced in how to handle their environments."

Although the lab has been home to physiological research since it was placed on the peak in the late 1960s, altitude sickness studies became even more relevant when troops were deployed to the mountains in Afghanistan after the Sept. 11, 2001, terrorist attacks on the United States. The Army sometimes moved faster than the soldiers' bodies could keep up. Most people need time to acclimate to the lower levels of oxygen in the air the higher they go, or they run the risk of developing acute mountain sickness or even more severe health issues, said USARIEM research physiologist Dr. Steve Muza, who has spent the last few summers on Pike's Peak.

"We scoop them up on helicopters, drop them off in the mountains, and they can become susceptible to problems," Muza said. "Our goal is to understand how the lack of oxygen affects soldiers biologically and physiologically, and then take the information to mitigate or reduce them getting sick."

The effects of AMS run from minor annoyances of light-headiness and a treatable headache to severe nausea. Cymerman said about 75 percent of people who venture above 8,000 feet without taking a few days to let their bodies adjust along the way will get some form of AMS. Fewer than 10 percent of people will react even more strongly, with life-threatening illnesses.

"Everyone has the same basic physiology," Cymerman said. "But some people can just adapt faster for unknown reasons."

Some of the medical breakthroughs from previous research on Pike's Peak have led to the Federal Drug Administration's only approved altitude sickness prevention medicine, and to better understanding of nutrition and hydration effects and other usable information for soldiers in the field.

"For instance, we demonstrated that we can improve performance by 25 percent by eating more carbohydrates," said Muza. "We're now in the process of developing carbohydrates supplement packages."

This year's research focused on determining the effects of hypoxic chambers in preparing for the altitude. World-class athletes use the low-oxygen chambers to help condition their bodies, and 20 soldiers and three civilians volunteered to sleep in them for seven days at USAREIM headquarters in Natick, Mass. They then were flown up to Colorado for a five-day stay on Pike's Peak to see if the chambers, which gave them the equivalent of acclimatization to 8,000-foot altitude, actually improved their performance and adjustment to the altitude.

Adapting faster may have been on the mind of Army Pvt. Scott Caine, a soldier who had a choice of studies in which he could be involved. Obviously not feeling well on his second day at Pike's Peak with a pale, greenish hue to his skin, he explained why he volunteered for something he was warned would make him sick, if only for a short time.

"This is one of the main studies I wanted to do," Caine said. "I'm heading to the 10th Mountain Division, which is deployed right now. If they can alleviate some of these problems before I get there, it would be great."

Caine and the other volunteers were tested both at Natick and on Pike's Peak for how sick they became, what kind of physical work performance they had, their mental performance and their physiological response to the altitude. Under the watchful eye of a doctor, researchers and other medical professionals, the volunteers usually adapted to the environment after a few days.

With peoples' lives involved, the researchers can't take their responsibility to the volunteers lightly, said Cymerman. Every year the scientists have to get the projected research approved by an Institutional Review Board and an approving official -- a three-month review process -- to ensure the volunteers are at minimal health risk.

"Although we are in a natural environment, it's not normal to take a soldier and very rapidly place him at more than 14,000 feet," he said. "If [someone] wants out of the study, we take him out. We make sure volunteers are protected."

While the USAREIM researchers protect their volunteers, Caine said, he was thinking about how his participation with the project was going to protect other soldiers.

"This is great to be a part of," he said between physical endurance tests. "A little bit of discomfort is OK, because the help we're giving to the soldiers outweighs anything I'm feeling right now."

(Sarah Maxwell works at the U.S. Army Medical Research and Materiel Command Public Affairs Office.)