Neurophysiological Effects of Intermittent Hypoxia on Brain Activity: A Systematic Review

Abstract

Intermittent hypoxia modulates brain function, producing adaptive and maladaptive neurophysiological effects depending on oxygen deprivation characteristics. Quantitative electroencephalography detects hypoxia-induced cortical alterations, but evidence remains fragmented. This systematic review synthesized evidence on intermittent hypoxia’s neurophysiological effects on brain activity assessed by electroencephalography. The review followed PRISMA 2020 guidelines. PubMed, Scopus, Embase, and Web of Science were systematically searched from June 1 to June 3, 2026. Eligible human studies evaluated intermittent hypoxia using quantitative electroencephalographic measures. Two reviewers independently performed study selection, data extraction, and methodological quality assessment using the Joanna Briggs Institute Critical Appraisal Tools. Owing to methodological heterogeneity, findings were synthesized narratively. Five studies involving 258 participants met the eligibility criteria. Intermittent hypoxia was associated with altered cortical oscillatory activity, including increased delta and theta power and reduced alpha activity. Controlled hypoxic interventions generally enhanced functional connectivity, whereas chronic pathological hypoxia in obstructive sleep apnea was associated with impaired network connectivity. Methodological quality ranged from moderate to high; however, the small number of heterogeneous studies warrants cautious interpretation. Quantitative electroencephalography is a promising biomarker, but larger standardized studies are needed before clinical translation.