Researchers have discovered that carefully controlled increases in carbon dioxide (CO₂) levels can significantly enhance the brain’s natural waste-removal system, a process critical for preventing neurological diseases. The findings, from a study led by neuroscientists at the University of New Mexico (UNM) and The Mind Research Network, suggest a potential new approach to combating conditions like Parkinson’s and Alzheimer’s.
The Brain’s “Sewage System”
For years, scientists have known that the brain clears toxins through the glymphatic system, a network of channels that flushes waste products during sleep. This system relies on the circulation of cerebrospinal fluid (CSF) to remove misfolded proteins and other harmful substances. However, this clearance process is often disrupted in neurodegenerative diseases like Parkinson’s, where sleep disturbances and reduced cerebral blood flow contribute to toxin buildup.
The glymphatic system was only fully understood in the last decade, making this discovery all the more important. The build-up of toxins in the brain is now widely thought to underlie the progression of neurological disease, though whether these toxins cause disease or are merely byproducts is still under investigation.
How CO₂ Manipulates Brain Clearance
The recent study found that intermittent hypercapnia – brief, rhythmic pulses of CO₂-rich air – can artificially stimulate the glymphatic system even while awake. Researchers believe that fluctuations in CO₂ levels cause blood vessels to expand and contract, boosting CSF flow. The results, published recently, showed that this technique improved waste clearance in both healthy participants and those diagnosed with Parkinson’s.
In experiments involving 63 older adults (30 with Parkinson’s), MRI scans confirmed that intermittent hypercapnia altered CSF flow. Follow-up tests on 10 participants (5 with Parkinson’s) revealed increased levels of waste products in the blood, indicating improved clearance. Notably, one participant with Alzheimer’s biomarkers showed a robust increase in amyloid-beta proteins in the blood after the CO₂ treatment, suggesting potential for clearing these toxins as well.
Implications and Future Research
The study’s findings suggest that manipulating CO₂ levels could be a novel therapeutic strategy for neurodegenerative diseases. Researchers are now exploring whether practices like yoga, tai chi, and qigong, which emphasize abdominal breathing, might achieve similar effects by naturally increasing CO₂ in the blood.
“We realized that we could reproduce, in the awake state, the glymphatic clearing response usually linked to deep sleep using intermittent CO₂,” explains neuropsychologist Sephira Ryman at UNM.
However, it remains unclear whether these changes are long-lasting or have a clinically meaningful impact on disease pathology. Further research is needed to determine the optimal CO₂ dosage, duration, and potential side effects before this approach can be considered a viable treatment.
The discovery opens new avenues for understanding and potentially preventing neurological decline, but it is still in the early stages of development.
