Abby Burkhart (left), Wesley Lefferts (center) and Carolyn Steffen (right) hoist an Iowa State flag while hiking through the Himalayas this spring. The expedition combined scientific research with the adventure of a lifetime. Photo courtesy of Wesley Lefferts. Larger image.
AMES, Iowa – If you’re going to study how high altitudes affect the human body, there’s no better laboratory than some of the world's tallest mountains.
An Iowa State University professor and two students recently returned from an expedition to the Himalayas, where they gathered data on how altitude affects blood flow to the brain. The project combined scientific discovery with a globetrotting adventure that could shed light on why some people experience altitude sickness more intensely than others.
Wesley Lefferts, an assistant professor of kinesiology who works in the Clinical Vascular Research Laboratory, first visited the Himalayas in 2018 as part of a research expedition. A second opportunity arose this year to join a multi-institutional research group that included scientists from Mount Royal University in Canada, UCLA and Syracuse University examining how the high altitudes affect the human body by comparing the physiological responses of team members with native Nepalese Sherpa. Lefferts invited Abby Burkhart and Carolyn Steffen, a pair of ISU students who worked in the Clinical Vascular Research Laboratory and contributed to the lab’s research, to join the expedition and use their research skills in the field. The expedition gave the students an opportunity to gather valuable data while experiencing the adventure of a lifetime.
Extreme science
The ISU trio set out on their journey on May 13 and returned on June 5. They spent 16 days hiking through the Himalayas in northern Nepal. Along the way, they studied how blood flows to the brain while the body acclimates to high altitude.
Burkhart and Steffen took readings from 17 subjects in two locations, at altitudes of around 4,500 feet and 14,400 feet. They turned their cramped quarters into a makeshift medical lab, using portable equipment to monitor each subject’s blood pressure and blood flow through the heart, carotid artery and another key artery in the brain. They also took ultrasound images of each subject’s heart and measured how well oxygen moved from their lungs to their blood.
The low air pressure at high altitudes reduces the amount of oxygen the body is able to take in. Around 14,000 feet above sea level and higher, some people experience intense fatigue, nausea and headaches, a condition referred to as acute mountain sickness.
“It’s not the same kind of fatigue as when you’re hiking up a hill in Iowa,” Lefferts said. “Your lungs simply are not getting enough oxygen into the body.”
Lefferts said physical fitness doesn’t reliably predict a person’s susceptibility to the condition, and the physiological processes at work at such high altitudes are poorly understood. It'll take some time to comb through the data they gathered, and the researchers aren’t ready to draw any conclusions yet. But they hope their efforts will shed light on why some people are especially susceptible to acute mountain sickness while others experience only mild symptoms.
Lefferts, Burkhart and Steffen experienced the phenomenon firsthand during their 16-day trek through the Himalayas. Both Lefferts and Steffen had to soldier through intense fatigue and headaches while Burkhart seemed to tolerate the altitude with less difficulty.
Before they could take any data, however, they had to figure out how to transport the requisite equipment, including a portable ultrasound machine, to the remote locations the expedition visited. Everything had to fit in their own backpacks or in the packs of one of a half-dozen yaks that accompanied the expedition.
The mental challenge
Steffen, who’s originally from Polk City, Iowa, and who plans to attend medical school after she finishes her undergraduate work at Iowa State, said the journey was a mental challenge as well as a physical one. She said she and Burkhart focused on moving at a deliberate pace during their ascents and taking regular breaks to conserve energy. They occupied their minds by mentally playing their favorite songs, creating a shared mental playlist of their favorite pop and country songs.
The sheer scale of the Himalayas can intimidate climbers who are already struggling with the thin atmosphere, Steffen said.
"You see this huge summit in front of you, and you just have to focus on getting to the next location,” Steffen said. “You can’t spend much effort even talking.”
The expedition included more than 40 travelers, composed of a mix of researchers, students and participants, some of whom belonged to the native Sherpa population who have genetic adaptations that help them perform at high altitudes. This mix of participants allowed the scientists to compare data between individuals who are adapted to lowland regions and individuals who are adapted to life at high altitudes.
The expedition also included a few Sherpa guides, who are familiar with the mountains and helped the group reach their destinations. The guides offered expert advice along the way that helped Steffen and Burkhart complete the journey.
“They told us, ‘Don’t look up. Just focus on your next step,’” Steffen said.
But it wasn’t just the altitude that left the ISU adventurers breathless. The mountain views along the journey proved to be spectacular. Like when the expedition reached its highest peak, a point known as Kala Patthar with an elevation of around 18,500 feet, in time to watch the sun come up over the nearby summit of Mount Everest.
Burkhart, from Dunlap, Iowa, graduated last semester with a degree in kinesiology and health and missed her commencement ceremony to join the expedition. She said she does not regret the decision.
“I loved every second of it,” Burkhart said. “It can hurt in the moment, but it’s worth it when you get to take in the view.”
