Vanderbilt Study Finds Meditation Mimics Sleep to Clear Brain Waste

Mindfulness meditation produces shifts in cerebrospinal fluid flow that closely resemble patterns observed during sleep, patterns previously associated in animal models with the brain's glymphatic waste-clearance network, according to research from Vanderbilt University published December 10, 2025.

The study, led by Manus Donahue, PhD, professor of Neurology and assistant vice chair for research at Vanderbilt Health, set out to answer a precise question. "We know that forms of meditation can represent distinct arousal states, and we asked the question: Does meditation alter fluid flow in the brain in a manner analogous to sleep and opposite to aging and neurodegeneration?" Donahue said.

Researchers recruited 50 participants: 23 experienced meditators and 27 controls with minimal meditation experience. Each person completed two 25-minute MRI sessions. Meditators practiced mind-wandering in the first session and silent, breath-awareness meditation in the second. Controls either repeated mind-wandering twice (13 participants) or followed mind-wandering with voluntary breath slowing (14 participants). That second control subgroup was deliberately designed to separate breathing-rate effects from the meditative state itself. The experienced meditators included practitioners from Isha Yoga and Vipassana traditions.

The team used phase-contrast MRI to measure CSF flow through the cerebral aqueduct, the narrow channel connecting the brain's ventricles, and BOLD MRI to track CSF oscillations near the cervicomedullary junction alongside hemodynamic activity across gray matter. During meditation, low-frequency CSF oscillations increased, and CSF signal power near the skull base rose within a specific frequency band: 3.7 to 5.3 cycles per minute. Crucially, CSF movement near the skull base synchronized inversely with hemodynamic activity across gray matter during meditation, a coupling pattern previously documented during sleep but absent during ordinary mind-wandering.

The slower breathing that often accompanies meditation did not explain the findings. "The effects we observed were not simply due to slower breathing; they were tied specifically to the meditative state," said Vago, a co-commentator quoted in the Vanderbilt press materials. "Because aging and brain disorders often disrupt CSF movement, our findings suggest that meditation could help support long-term brain health by enhancing the brain's own waste-clearance processes."

The glymphatic system, which becomes most active during slow-wave sleep in animal models, clears toxins, metabolic byproducts, and proteins that accumulate during waking hours. Efficient CSF flow is particularly relevant for conditions linked to problematic molecular buildup: Alzheimer's disease, Huntington's disease, and Parkinson's disease are all named in the Vanderbilt research framing. CSF circulation efficiency is also known to deteriorate with age, making the potential for a practice-based intervention especially significant for the research community.

Important caveats apply. The study measured fluid dynamics, not actual waste removal. No metabolite clearance, amyloid removal, or clinical outcome was assessed. The phrase sometimes used in popular coverage, that meditation "flushes" the brain, goes beyond what the data demonstrate. What the study shows is a measurable shift in CSF behavior that structurally resembles sleep-state patterns; whether that shift translates to genuine waste clearance in humans remains an open question requiring further study.

Co-first author Bryce Keating worked alongside Donahue on the research, with additional Vanderbilt contributors including Kilian Hett, PhD; Ciaran Considine, PhD; Maria Garza, MBA; Caleb Han; Colin McKnight, MD; and Daniel Claassen, MD. The work was funded by National Institutes of Health grants R01AT011456 and R01AG083159. A separate systematic review in Frontiers in Neuroscience by Pihala T and Kiviniemi V, circulating in the research community, has highlighted an emerging connection between mitochondrial function and glymphatic flow, noting that human data in this area remain limited.

For practitioners whose daily sits have long felt genuinely restorative, the Vanderbilt findings offer the most physiologically specific evidence yet that the comparison to sleep may be more than metaphor.