Neuroinflammation is the immune response of tissue in the brain and spinal cord, carried out mainly by the resident immune cells of the central nervous system — microglia and astrocytes. A short burst of it is useful: microglia clear debris, dying cells and pathogens, then quiet down. Problems start when the trigger never goes away, and the response stays partly switched on for years. That low-grade, persistent version is what researchers mean when they connect Neuroinflammation to brain aging.
What it measures
Neuroinflammation is a process, not a number on a lab slip. There is no routine blood test for it and no agreed cut-off that separates normal from abnormal. What exists are indirect windows on the same process, each with its own limits.
- PET imaging. Tracers that bind TSPO, a protein that increases when microglia activate, show where in the brain the response is concentrated. Used in research, rarely in clinical care.
- Spinal fluid markers. Proteins such as GFAP, YKL-40 and soluble TREM2 rise when glial cells are activated. They require a lumbar puncture and are interpreted against the laboratory’s own reference population.
- Blood markers. GFAP is now measurable in plasma, and general inflammatory markers such as hs-CRP — high-sensitivity C-reactive protein are sometimes used as a rough proxy. They reflect inflammation in the body as a whole, not specifically in the brain.
- Tissue. Examining brain tissue after death remains the only direct confirmation.
Because assays, tracers and reference populations differ between centers, values from one study or laboratory do not transfer to another. Treat any single result as a research signal, not a diagnosis.
Why it matters for longevity
Activated microglia are found clustered around amyloid plaques and tau tangles in aging brains, and markers of glial activation tend to rise with age even in people without diagnosed disease. In observational cohorts, higher inflammatory markers in midlife are associated with faster cognitive decline and a greater risk of dementia decades later. Chronic activation is also associated with Neurodegeneration, depressive symptoms, and slower recovery after surgery or stroke.
The honest caveat: most of this evidence is associative. Whether sustained neuroinflammation drives the damage, follows it, or both, is still unsettled — and trials of general anti-inflammatory drugs to prevent dementia have not shown the benefit that the observational data suggested.
What changes it
Nothing on this list is proven to lower a brain inflammation reading. What follows are the levers that move whole-body inflammation, which travels with the brain signal.
- Sleep. Restricted or fragmented sleep raises circulating inflammatory markers, and clearance of metabolic waste from brain tissue is greater during sleep.
- Regular aerobic exercise. Associated with lower inflammatory markers and better cognitive outcomes in older adults.
- Diet pattern. Mediterranean-style and MIND-style eating — fiber, legumes, olive oil, oily fish, few ultra-processed foods — is associated with lower inflammatory markers and slower cognitive decline.
- Excess body fat, especially visceral fat. A continuous source of inflammatory signaling; losing it lowers those markers.
- Smoking, heavy alcohol, untreated infections and gum disease. All keep the immune system engaged.
- Not in your control. Chronological age, APOE genotype, and a history of significant head injury all shift the baseline.
Related reading
- How to Eat for Brain Health: A Cognitive Longevity Guide
- Chronic Inflammation and Aging: Inflammaging
- How Sleep Affects Aging and How Much You Need
- Neurodegeneration
Disclaimer. This article is for information only and does not replace medical advice. Talk to a qualified clinician before changing anything about your health.