Brain water dynamics across sleep stages measured by near-infrared spectroscopy: Implications for glymphatic function.

ABSTRACT: This study investigates brain water dynamics across the sleep-wake cycle using near-infrared spectroscopy (NIRS) and linear mixed-effects modeling, motivated by prior observations that glymphatic activity increases during non-rapid eye movement (NREM) and decreases during REM sleep. Forty-one healthy volunteers underwent polysomnography with concurrent cerebral NIRS, with measurements taken 30 minutes before sleep, throughout the night, and for 60 minutes after waking. Brain water content (arbitrary unit, A.U.) was block-averaged for 5-minute epochs and analyzed across WAKE→NREM, NREM→WAKE, NREM→REM, and REM→NREM transitions. Water content significantly increased during WAKE→NREM (0.57 A.U., d = 0.77, p < 0.001) and decreased during NREM→WAKE (-0.93 A.U., d = -1.25, p 

SUBMITTER: Yoon JE 

PROVIDER: S-EPMC12202386 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature