Bolivian High-Altitude Explorations: Sleep, Oxygen, and Teen Cognition
A collaboration between the University of Zurich (UZH) and the Bolivian Private University of Santa Cruz (UPSA) investigates how oxygen saturation levels during sleep affect cognitive function among teens living at elevations above 3,600 meters, highlighting insights into high-altitude health.
Studying Sleep at Extreme Heights
When most people imagine the challenges of living at high altitudes, they think of thin air and physical fatigue. Now, researchers from the University of Zurich (UZH) and Bolivia’s Private University of Santa Cruz (UPSA) are focusing on a less obvious but significant aspect: the way adolescents breathe at night. According to neuroscientist Edith Schneider of UZH, who leads the project, “It has been an analysis of sleep polygraphy in adolescents living at high elevations to see how they breathe.” Speaking with EFE, she added, “We measure oxygen saturation and respiration patterns, checking for sleep apnea episodes. The question is whether higher altitude leads to greater risk and how that might affect a teenager’s learning abilities.”
To conduct their study, Schneider’s team zeroed in on more than 200 teenagers in two cities: La Paz, which sits at about 3,600 meters (nearly 11,800 feet) above sea level, and El Alto, located at over 4,100 meters (approximately 13,450 feet). The researchers looked at sleep quality, breathing irregularities, and other nocturnal markers to uncover any links between reduced nighttime oxygen levels and cognitive performance. They also measured physiological indicators like hemoglobin concentration, oxygen saturation in the blood, and the presence of apnea events—moments during sleep when breathing pauses or becomes very shallow.
Adolescent Bodies and Minds Under Pressure
Adolescence is a time of change in body plus thought processes, so it is important for researchers to learn about dangers connected to residence at high altitudes. Schneider told EFE: “We selected adolescence because puberty causes substantial body changes then.” “It is an ideal period to detect any respiratory disorders and also to determine if there are learning problems associated with altitude.”
During the study, physiological readings were correlated with various psychological tests designed to evaluate attention span, memory, reaction time, and reasoning skills. “Our initial hypothesis was that beyond 4,000 meters, breathing difficulties could be more pronounced,” Schneider said. The data confirmed that teenagers in El Alto, which sits higher than La Paz, experienced more frequent oxygen desaturation and sleep apnea events. Yet, while these findings might sound alarming, Schneider was quick to put them into perspective: “It’s normal because it’s higher. What we need to do is establish how people at altitude breathe and what their baseline values are for both respiration and oxygenation.”
One of the most important dimensions of the study is its potential benefit for teenagers and their families. Schneider noted that many adolescents living above 3,600 meters are well-adapted to the environment, but some could be at higher risk of oxygen desaturation, which might affect academic performance. “If a teenager is falling into that risk category, it’s critical to identify that early,” she emphasized. “The problem might not be huge, but it must be recognized and addressed in time.”
Defining New Standards in Altitude Medicine
Bolivia has striking mountain areas. They attract many tourists. Science does not fully understand how people’s bodies function at high altitudes. This is particularly true for the lungs. According to Schneider, “This is extremely important for high-altitude medicine in order to establish normal standards—so we don’t inadvertently apply parameters that aren’t suited to the region.” She told EFE that, too often, the medical community uses sea-level benchmarks to judge what is “normal,” potentially leading to misguided diagnoses or interventions for populations living thousands of meters above sea level.
The University of Zurich supported and coordinated the project through its Institute of Veterinary Physiology, overseeing the physiological measurements. Meanwhile, UPSA, under the leadership of Bolivian investigator Nicolás Arancibia, managed participant recruitment and the cognitive testing portion of the research. Both partners see this collaborative model as a key stepping stone toward understanding how altitude impacts health—from birth through adulthood.
Schneider believes this type of investigation is especially crucial in Bolivia, where cities like El Alto have high population densities. With over 885,000 residents, El Alto stands as one of the world’s largest high-altitude urban areas. Yet, as Schneider told EFE, “Altitude medicine in Bolivia is totally neglected. It hasn’t been taken into account at all, and there have been no efforts to understand, for instance, how respiration works at high elevations.” She advocates turning altitude medicine into a “national priority” for her country.
Expanding Research Beyond the Andes
While the current study focuses on La Paz and El Alto, the researchers are already looking beyond Bolivia’s high plains. The plan is to replicate the tests at various altitudes around the globe in order to compare results and glean broader insights into adolescent health. “We want to see if the proportion of risk remains the same,” Schneider said. Upcoming sites may include urban centers situated above 2,500 meters, like locations in Kyrgyzstan, and lower-altitude environments, such as Santa Cruz, Bolivia’s largest metropolis at 400 meters above sea level. “This will give us a complete picture, from high altitudes to lower ones,” she added.
Such cross-continental collaboration could illuminate how different groups adapt—or struggle to adapt—to diverse environmental challenges. Differences in diet, cultural practices, and even genetic backgrounds might influence the degree to which teenagers can handle reduced oxygen levels. The research team aims to use comprehensive data on respiration, blood saturation, and cognitive health to establish standard guidelines that governments and healthcare providers can implement to improve the well-being of youth who reside at high altitudes.
Schneider will present her findings at the global high-altitude medicine conference which is taking place in Kyrgyzstan from April 24 to 26. The location of the conference in a mountainous area emphasizes how globally relevant her work is. According to Schneider in an EFE report we must determine what constitutes normal physiological conditions for people who have lived their entire lives at high altitudes. Understanding baseline respiration and oxygenation values helps detect potential risks at an earlier stage.
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This study brings attention to an essential yet frequently ignored component of life at high altitudes. For adolescents navigating the challenges of puberty, academic demands, and rapidly shifting social lives, the added factor of diminished oxygen during sleep might be an invisible obstacle—one that can only be addressed through dedicated scientific inquiry and consistent medical screening. Thanks to this Bolivian-Swiss partnership, the adolescent residents of some of the highest cities on Earth might soon benefit from a more tailored healthcare approach, ensuring their bright futures remain as limitless as the Andean sky above.
