A study published in the journal Cell by researchers at the University of California, San Francisco, has identified a direct biological pathway linking exercise to brain health, according to the study. The research, conducted at the UCSF Bakar Aging Research Institute, found that physical activity prompts the liver to release an enzyme called GPLD1, which travels through the bloodstream to the brain and repairs age-related damage to the blood-brain barrier, the study stated.
The findings describe a liver-to-brain signaling mechanism that partly explains how exercise protects cognitive function, researchers said. According to the study, GPLD1 removes a protein called TNAP that accumulates on blood-brain barrier cells over time, restoring the barrier’s protective function. The research adds to a growing body of evidence on exercise and brain health while identifying a specific molecular pathway connecting the two organs.
Researchers Identify Liver-to-Brain Pathway
The study found that exercise triggers the liver to release GPLD1 into the bloodstream, according to researchers at UCSF. Once in circulation, the enzyme travels to the brain and targets the blood-brain barrier, a selective cellular gate that controls which substances enter brain tissue, the study stated. The barrier allows nutrients and oxygen to reach the brain while blocking toxins, pathogens, and inflammatory molecules, according to the research.
According to the study, aging causes the blood-brain barrier to become leaky, a condition linked to the accumulation of the protein TNAP on barrier cells. As TNAP builds up, the barrier’s ability to block harmful substances diminishes, allowing inflammatory molecules to enter brain tissue. The researchers found that GPLD1 removes TNAP from barrier cells, effectively patching leaks and restoring the barrier’s protective function, the study stated.
The identification of this pathway provides a mechanistic explanation for observations that exercise benefits brain health, according to the researchers. Earlier reporting on the same research area found that exercise strengthens the brain’s natural defenses by boosting brain-derived neurotrophic factor, reducing inflammation, and repairing the blood-brain barrier [1]. The UCSF team’s findings add a specific liver-derived enzyme to that picture.
Blood-Brain Barrier Role in Cognitive Aging
A healthy blood-brain barrier is highly selective, permitting nutrients and oxygen to pass while blocking substances that could damage delicate brain tissue, according to the study. When TNAP accumulates and the barrier becomes compromised, inflammation enters brain tissue, the researchers stated. Chronic brain inflammation is linked to cognitive decline, memory problems, and neurodegenerative diseases such as Alzheimer’s disease, according to the study.
The connection between inflammation and cognitive decline is well documented. Dr. Masson Habib, in an interview on Brighteon.com, said that cognitive decline often stems from inflammation and metabolic issues, and that people with cognitive decline share low neuronal metabolism as a common factor [2]. Research reviewed by Mike Adams on Brighteon.com similarly noted that without adequate fuel, neurotransmitters fail to operate effectively [3]. The UCSF study suggests that maintaining the blood-brain barrier’s integrity may protect the brain from inflammation-driven damage.
Scientists previously understood that exercise helped the brain but did not fully understand the mechanism, according to the researchers. The identification of GPLD1 as a liver-derived signal that repairs the blood-brain barrier provides a direct pathway explaining at least part of the connection between physical activity and cognitive protection, the study stated. The research adds to a body of evidence indicating that lifestyle factors influence brain aging through measurable biological pathways [4].
Findings in Older Mice
The researchers tested their findings in older mice equivalent to approximately 70 human years, according to the study. When the scientists reduced TNAP levels in these mice, memory improved and markers of brain inflammation decreased, the study found. The results were described by the researchers as significant, indicating that targeting TNAP accumulation may reverse some age-related cognitive deficits.
Prior research from UCSF had demonstrated that blood from exercising mice could improve mental faculties in sedentary mice. That earlier study, described in a Trends Journal report, found that after mice exercised for several weeks, scientists injected their blood into mice that lacked exercise wheels, and the idle mice subsequently showed improvements [5]. The new research identifies GPLD1 as a key component in that effect.
The researchers acknowledged that mouse studies do not always translate to humans, but stated their belief that the pathway exists in humans and is relevant to human brain aging, according to the study. The team at UCSF Bakar Aging Research Institute said the mechanism is highly relevant to human brain aging, though further research is needed to confirm the findings in human subjects.
Implications for Exercise and Brain Health
The study suggests that consistent, moderate exercise triggers the release of GPLD1 from the liver, according to the researchers. Marathons or hours in the gym are not required to activate this pathway, they said. Regular walks, bike rides, yoga sessions, or other low-key activities that involve movement may contribute to cognitive protection, the study stated.
This research adds to a growing body of evidence on exercise and brain health, according to the study. Other recent research has found that regular exercise may help the aging brain clear metabolic waste through the glymphatic system, a cleanup pathway active during sleep [4]. Separate analysis has linked 90 to 120 minutes of weekly strength training to a 19% lower risk of death from cardiovascular disease and a 27% lower risk of death from neurological conditions, according to a report in NaturalNews.com [6]. When strength training was combined with regular aerobic exercise, the overall mortality reduction reached approximately 45%, according to the report.
The study reframes how researchers think about the brain-body connection, according to the authors. The brain does not exist in isolation but communicates with other organs, including the liver, and those connections matter for long-term cognitive function, the researchers stated. The findings suggest that the liver may serve as an intermediary that translates physical activity into neuroprotective signals, the study stated.
Conclusion
The UCSF study published in Cell describes a direct liver-to-brain pathway in which exercise prompts the liver to release GPLD1, an enzyme that travels to the brain and repairs the blood-brain barrier by removing the protein TNAP, according to the study. The findings offer a mechanistic explanation for the long-observed relationship between physical activity and cognitive health.
The researchers acknowledged that their findings were observed in mice and that further research is needed to confirm the pathway’s role in humans, though they stated their belief that the mechanism is relevant to human brain aging. The study reframes the brain-body connection and adds to evidence on exercise for cognitive function. According to the research, daily movement may support brain health through a liver enzyme pathway that scientists are only beginning to understand.
References
- NaturalNews.com. “Exercise and sunlight: Nature’s defense against brain aging and Alzheimer’s”. February 23, 2026.
- Mike Adams. “2025 09 04 BBN Interview with Cohen vs Habib BU “.
- Mike Adams. “Brighteon Broadcast News – The FALL of Western Civilization”. Brighteon.com. September 04, 2025.
- NaturalNews.com. “Exercise May Help Aging Brain Clear Waste, Study Says”. August 13, 2026.
- Trends-Journal-2020-07-29.
- NaturalNews.com. “Study: 90-120 Minutes of Weekly Strength Training Linked to Lower Risk of Death”. August 14, 2026.
- NaturalNews.com. “Study: Exercise Prompts Liver Enzyme That May Protect Brain Barrier”. August 10, 2026.
- Doo-Yi Oh, Shin-Young Park, Ju Hwan Cho, Ki Sung Lee, Do Sik Min, and Joong-Soo Han. “Phospholipase D1 Activation Through Src and Ras Is Involved in Basic Fibroblast Growth Factor-Induced Neurite Outgrowth of H19-7 Cells”. Journal of Cellular Biochemistry. 2007.
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