20 May 2010

Researchers go to the mountain

What if you want to study what happens to mountain climbers' lungs? There's really no way to do it except climb a mountain, equipment in tow.

Science is challenging enough in a comfortable lab: Endless grant proposals, failed experiments, and pressure to publish papers.

But what if you want to study what happens to mountain climbers' lungs? There's really no way to do it except climb a mountain, equipment in tow.

In 2005, Dr Konrad E. Bloch, of the University Hospital of Zurich, Switzerland, and colleagues recruited 35 healthy mountaineers for what seemed more like adventure travel than medical research.

The group flew to Islamabad in July and then went on a five-day bus trip to the 7,546m Mount Muztagh Ata, at the edge of the Tibetan Plateau in China.

There was a sacrifice to science even before the team reached the mountain's base: One of the mountaineers came down with traveller's diarrhoea and had to return home.

Bloch, who was 50 at the time and had only some climbing experience, said he tolerated the altitude well. But it wasn't easy.

"It was a real challenge because as an investigator I had to get up earlier in the morning, one hour before the others, to set up equipment."

He and a fellow physician would then let the study participants go ahead, catching up with them later.

"When the others went to the tent for cooking and resting, we had to stay out," Bloch said.

Challenges in the field

The researchers assigned the climbers, the oldest one 65, to one of two groups that would climb the mountain at different speeds. Seventeen never made it to the summit: Along the way, they succumbed to altitude sickness or exhaustion and had to return to base camp.

On some nights during the three-week ascent, the climbers would don a high-tech shirt - far from earlier days' clunky equipment - with built-in sensors that measured their breathing and heart patterns, along with their blood oxygen levels.

The effort paid off. In a study published in the American Journal of Respiratory and Critical Care Medicine, Bloch's team reported that oxygen blood levels increased as the climbers got accustomed to the harsh environment, despite the troubled breathing patterns seen at high altitudes.

In fact, those so-called periodic breathing patterns - in which climbers take a few deep breaths, then breathe shallowly or stop breathing altogether for a short while - increased in frequency and could actually be helpful.


"We have to accept periodic breathing as an unfortunate byproduct of effective general adaptation," said Dr Martin Burtscher, president of the Austrian Society for Mountain Medicine, who was not involved in the study.

"In my opinion these results may soothe high-altitude mountaineers by showing that periodic breathing is normal at high altitude," Burtscher, of the University of Innsbruck, said in an e-mail to Reuters Health.

"However, one should not forget that high altitude is a hostile environment for human life and periodic breathing contributes by disturbing sleep quality," he added.

Bloch would know. The day before his team's final ascent to Muztagh Ata's top, the only other physician in the camp suffered a fluid buildup in his lungs that turned him all blue. But Bloch treated him successfully, and the next day they reached the summit.

"That was exciting," Bloch says. - (Frederik Joelving/Reuters Health, May 2010)

SOURCE: American Journal of Respiratory and Critical Care Medicine, online May 4, 2010.


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