UBC Okanagan researchers studying high-altitude human populations 

Investigators strive to understand how some populations can adapt—or mal-adapt—to their habitat

click to enlarge PHOTO SUBMITTED - Cardiff University's Mike Stembridge, one of the researchers involved with UBC Okanagan's high-altitude study, at the Pyramid lab in Everest.
  • Photo submitted
  • Cardiff University's Mike Stembridge, one of the researchers involved with UBC Okanagan's high-altitude study, at the Pyramid lab in Everest.

Whistler is a community full of people that pride themselves on accomplishing impressive athletic feats at high altitudes.

But if you ask University of British Columbia Okanagan PhD candidate and high-altitude researcher Mike Tymko, we've got nothing to brag about.

"They completely destroy us when it comes to high altitude living," said Tymko of the high-altitude indigenous populations he's studied in recent years.

"They're just so much better equipped and adapted, from a physiological standpoint, to just be functioning at a high level at high altitudes."

During one expedition to Nepal, it took researchers 10 days to trek to their site. "We've got equipment on our backs, so do the Sherpa, our guides," explained Tymko. "Quite often, if (the Sherpa got) a phone call saying (help was needed) a couple of kilometres ahead, they'll run out—they'll drop their backpack or have their backpack still on—and they'll take off at a full-on sprint.

"Whereas, if you're walking at that kind of altitude, for most people like us, just at a normal walking pace you're barely hanging on. "

While in Nepal, researchers stayed at over 5,000 metres in elevation for a month. (To put that in perspective, the highest peak in North America is Denali, at 6,190 metres. Whistler Mountain's peak has an elevation of 2,181 metres.)

So far, Tymko and his research teams have studied Sherpa in the Himalayas, and plan to study another indigenous population living at high altitude in Ethiopia, with "pretty sophisticated, invasive" and "complex" physiology experiments looking at properties like the nervous system, brain, heart and lung function.

So how are these populations able to function so well compared to their fellow human beings? "We don't know the full story yet, but they're just able to utilize oxygen at a higher capacity compared to us," Tymko said. "That would be the overview."

Now, he and professor Phil Ainslie—a Canada Research Chair in cerebrovascular physiology who has spent his career studying hypoxia, better known as reductions in oxygen tension, content (hemoglobin) or both—are organizing a large-scale, month-long research expedition to Peru, which just began. Their team, made up of 45 investigators from universities around the world, will study the local Andean population living at Cerro de Pasco, a mining town with an altitude of 4,330 metres.

"What I'm most interested in is the comparison between the difference in evolutionary patterns of the high-altitude adaptations—so that's the Sherpa, the Andeans, and Ethiopians," said Tymko, explaining that the team's five-year research plan is to conduct a similar set of experiments in each of those three populations.

"That's three different high-altitudes (indigenous populations) that have all genetically adapted to high-altitude living in a low-oxygen environment, separately, using different strategies ... I don't know of anyone that's really done what we're doing."*

There's a bit of urgency behind the desire to carry out this research, Tymko added. "We probably only have another about 30 to 50 years to test these (peoples)," he said explaining that the development of the internet has led many high-altitude indigenous people to seek low-land jobs, and thus creating families with indigenous low-landers. "Their genetics are slowly becoming lost in different gene pools," said Tymko.

In Peru, researchers will also work with a small percentage of the indigenous highlander Andeans who have developed a genetic maladaptation. That maladaptation has led them to develop a condition called chronic mountain sickness, caused by an overproduction of red blood cells. "Their body is making too many of them, so their blood becomes very thick and they can get very sick because it's almost like (their hearts) are pushing sludge around ... They're very prone to any cardiovascular events, and they also don't feel very good, but the only way to treat it is to come down from altitude," Tymko explained.

However, the sickness is something the group pushes through daily in order to continue making a decent living.

The team will carry out about 15 studies that will compare themselves—regular lowlanders—with the sick highlanders, as well as normal Andean highlanders who do not suffer from the maladaptation, with 45 to 60 patients in each group.

Through their research, investigators hope they can come to understand how some populations can adapt—or mal-adapt—to their habitat, and come up with new methods to treat illnesses like the one their research subjects suffer from.

*Clarification: Tymko and his team are “the first to conduct such invasive, sophisticated, experiments in these populations,” he explained. However, he acknowledged that several other researchers, including the late Peter W. Hochachka, a professor in the Department of Zoology, Radiology and Sports Medicine at UBC and a part-time Whistler resident, have previously investigated the different strategies that high altitude people, including indigenous populations like Quechuas in the Andes and Sherpas in Nepal, have used to adapt to low oxygen availability, as well. Some of that research, including work with those populations’ blood physiology, can be found in Chapter 5 of Hochachka’s book Biochemical Adaptation, (co authored with George N. Somero) entitled Human Hypoxia Tolerance.

“In recent years, the technological advances have been substantial - allowing us to measure things that we have never been able to before,” Tymko explained.


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