Intermittent hypoxia preconditioning can attenuate acute hypoxic injury after a sustained normobaric hypoxic exposure: A randomized clinical trial.

"tables s1-s3 data availability statement the datasets supporting the conclusions of the current study are available from the corresponding author upon reasonable request."

"CONFLICT OF INTEREST STATEMENT The authors declare no conflicts of interest."

"FUNDING INFORMATION This work was supported by National Key R&D Program of China (grant number 2022YFC3501005) to Wang Y. Ji XM was supported by the National Natural Science Foundation of China (grant number 82027802)."

"A total of 100 healthy subjects residing at low altitudes were recruited to participate in the study and randomized to the control group and IH group at a 1:1 ratio according to a computer‐generated randomization table from March 1, 2023, to September 1, 2023. A comprehensive and detailed physical examination and clinical evaluation were performed before enrollment to single out the ones who met the inclusion criteria and who needed to be excluded. The inclusion criteria included: (1) healthy lowlanders of both sexes aged from 18 to 45 years old with body mass index between 19 and 24.9 kg/m2; (2) resting peripheral oxygen saturation (SpO2) of more than 90%, cerebral oxygen saturation between 58% and 82%, heart rate between 60 and 100 beats/min, and blood pressure within the normal range (90–130/60–80 mmHg). Exclusion criteria were a history of respiratory, cardiovascular, neurological, and hematological diseases, including chronic respiratory diseases, cerebrovascular diseases, and anemia. Subjects under the categories of menstruating, pregnant, lactating, smoking, alcohol intake habits, and long‐living at altitudes >1200 m, as well as high‐altitude exposure in the last 6 months, were also excluded. Subjects were asked to wean off caffeine, alcohol, functional beverages, and strenuous exercise throughout the testing period. All the subjects were apprised of the scope of the experiment and provided informed written consent. This study was conducted in accordance with the reporting guidelines of Consolidated Standards of Reporting Trials, and had been approved by the Ethics Committee of Xuanwu Hospital, Capital Medical University, and registered on the site ClinialTrials.gov (https://clinicaltrials.gov; NCT05733338)."