Researchers have presented findings suggesting that short pulses of inhaled carbon dioxide may activate the brain’s glymphatic system, helping clear toxic proteins linked to Alzheimer’s disease.
The 2025 study, led by Dr. Sephira Ryman of the University of New Mexico School of Medicine and the Mind Research Network, indicates that intermittent exposure to CO2-enriched air can promote the movement of cerebrospinal fluid to flush out proteins such as tau. The work was presented at the Alzheimer’s Association International Conference (AAIC) in London, held July 12–15, 2026.
The glymphatic system functions as the brain’s waste-removal pathway. It is most active during deep sleep and often impaired in neurodegenerative conditions. Researchers used masks delivering alternating bursts of CO2-rich air to participants. They observed improved clearance of tau protein from the brain and elevated levels of amyloid beta in the bloodstream, indicating the proteins were being evacuated.
Study Details and Methods
The approach builds on earlier research by Ryman’s team. In 2025, they published findings in NPJ Parkinson’s Disease showing that intermittent hypercapnia — controlled low-level CO2 exposure in on-off cycles — increased cerebrospinal fluid inflow and boosted clearance of proteins including alpha-synuclein, amyloid beta, and phosphorylated tau in both healthy individuals and those with Parkinson’s disease.
For the Alzheimer’s-focused presentation, the team applied similar techniques. Participants used masks for brief sessions totaling around 30 minutes. The CO2 pulses cause blood vessels in the brain to dilate and constrict, acting like a pump to drive fluid movement through brain tissue.
“This dilation and constriction essentially serves as a pump that clears waste from the brain,” Ryman stated in coverage of the presentation.
The study is described as small and preliminary. Larger clinical trials are needed to assess long-term safety, efficacy, and benefits for cognitive decline.
History of Glymphatic Research
The glymphatic system was discovered in the early 2010s by researchers at the University of Rochester. It uses perivascular channels to clear metabolic waste, including proteins that accumulate in Alzheimer’s and other dementias. Sleep disruption and aging reduce its efficiency, contributing to disease progression.
Previous efforts to enhance glymphatic function have focused on sleep improvement and exercise. Ryman’s team explored non-invasive methods to replicate sleep-like clearance while awake using controlled breathing or CO2 exposure.
Alzheimer’s Impact in the United States
An estimated 7.4 million Americans age 65 and older are living with Alzheimer’s dementia in 2026. This figure represents a significant portion of the broader dementia population. The number is growing due to the aging U.S. population. Projections indicate it could reach 13.8 million by 2060.
Alzheimer’s remains a leading cause of death and carries substantial costs for families and the healthcare system. Additionally, analyses place the costs of dementia in the United States at $818 billion in 2026, per a USC-led study published in Alzheimer’s & Dementia.
Potential Impacts, Pros and Cons
If confirmed in larger trials, the CO2 approach could offer a low-cost, non-invasive option that complements existing therapies. It aims to address a root mechanism — waste accumulation — rather than only symptoms.
Advantages include accessibility for home use and avoidance of pharmaceutical side effects. However, high-dose CO2 inhalation carries risks if not properly controlled, such as changes in blood pH or respiratory effects. Safety in vulnerable populations, including those with respiratory conditions, requires careful study.
Researchers plan further trials to determine optimal protocols, long-term outcomes, and effects on cognitive function. The work remains in the investigational stage and is not yet recommended as a treatment.
Provided by Dallas Express
