Sleep at high altitude: A bibliometric study and visualization analysis from 1992 to 2022

As an important monitoring index for adaptation to hypoxia, sleep may reflect the adaptive state of the body at high altitudes. The literature has shown a link between altitude and sleep problems, and sleep changes have become a common problem for individuals at high altitudes, negatively impacting their physical and mental health. As research on high-altitude sleep has gained attention in recent years, the publishing volume has increased worldwide, necessitating a more comprehensive understanding of this field. This manuscript evaluates the key themes and emerging trends in high-altitude sleep over the past few decades and predicts future research directions.

Articles related to high-altitude sleep published from 1992 to 2022 were retrieved from the Web of Science Core Collection, and the relevant literature characteristics were extracted after the screening. Then, bibliometric analyses and visualizations were performed using Microsoft Excel, CiteSpace, VOSviewer, and an online analysis platform (http://bibliometric.com).

A total of 1151 articles were retrieved, of which 368 were included in the analysis, indicating a gradually increasing trend. The United States, Switzerland, and China have made significant contributions in this field. Bloch KE from the University of Zurich was determined to be the most productive and academically influential author in this field. The highest-yielding journal was High Altitude Medicine & Biology. Initially, altitude training was the primary research topic. Currently, research focuses on sleep disorders and sleep apnea. In the coming years, keywords such as "sleep quality," "prevalence," and "obstructive sleep apnea" will attract more attention.

Our findings will assist scholars to better understand the intellectual structure and emerging trends in this field. Future developments in high-altitude sleep research are highly anticipated, particularly in terms of sleep quality at high altitudes and its associated prevalence. This research is also crucial for the improvement and treatment of symptoms during nocturnal sleep in patients with chronic hypoxia due to cardiopulmonary diseases at high altitudes.