What is chronic inflammation (inflammaging) and how is it measured?

01Acute vs chronic inflammation

The first distinction to understand is that acute and chronic inflammation are different biological states, with different drivers, different markers, and different clinical meaning.

Acute inflammation is the rapid, robust response of the immune system to an insult - an infection, an injury, an exposure to a toxin. It is characterized by classical signs: redness, heat, swelling, pain. At the molecular level, it involves a coordinated cascade of cytokines (especially IL-6, TNF-alpha, IL-1) and acute-phase proteins (CRP, fibrinogen, serum amyloid A) that mobilize the immune system to address the insult, contain the damage, and then resolve.

Acute inflammation is, in almost all cases, good. It is the immune system doing its job. The clinical concern with acute inflammation is when it fails to resolve - when the insult persists, the regulatory mechanisms that should turn it off do not engage, and the temporary activation state becomes permanent.

Chronic inflammation is what happens when that resolution fails - or when low-level activation accumulates from many sources over time without any single dominant insult. The hallmark of chronic inflammation is sustained, low-grade activation of innate immune pathways, often without obvious symptoms. The person feels relatively well. The system is in slow, persistent overdrive.

The biology of chronic inflammation involves many of the same cytokines and pathways as acute inflammation, but at lower magnitudes and on extended timescales. Over years and decades, this sustained low-grade activation damages tissues, accelerates cellular aging, promotes atherosclerosis, contributes to insulin resistance, drives neurodegeneration, and elevates the long-term risk of most age-associated diseases.

This is what we mean when we talk about inflammaging.

02What is inflammaging?

The term was coined by Claudio Franceschi, an Italian immunologist, in a foundational 2000 paper to describe a specific phenomenon: the gradual, age-related increase in systemic, sterile, low-grade inflammation that occurs in essentially every human being as they age, and that contributes mechanistically to most major age-associated diseases.

Inflammaging has several defining features:

• It is sustained - present continuously rather than episodically
• It is low-grade - at any given moment, the markers are only mildly elevated
• It is systemic - measurable in blood, not confined to one organ
• It is sterile - not caused by infection, even though it uses the same molecular machinery
• It is multi-causal - driven by accumulated cellular damage, metabolic dysfunction, gut microbiome shifts, accumulating senescent cells, chronic psychological stress, and lifestyle exposures

It is also, importantly, modifiable. The major drivers of inflammaging are largely the same as the major modifiable drivers of accelerated aging: poor sleep, smoking, alcohol, ultra-processed diet, sedentary behavior, chronic stress, obesity. Address these, and you address inflammaging. Refuse to address them, and inflammaging will mark its presence on essentially every aspect of your long-term health.

In the published literature, inflammaging is now considered one of the central mechanistic links between lifestyle and longevity. The 2023 update to the Hallmarks of Aging framework (López-Otín et al., Cell, 2023) lists chronic inflammation as one of the integrative hallmarks of biological aging.

03Why measuring chronic inflammation is hard

If chronic inflammation is so central to aging, why is it not measured routinely in clinical practice the way blood pressure or cholesterol are? The answer is that, until recently, the available biomarkers were poorly suited for the task.

The problem with high-sensitivity CRP

CRP is the most widely measured inflammatory marker in clinical practice. It is excellent for what it does well: detecting acute or sub-acute inflammatory states. The problem for inflammaging tracking is that CRP is sensitive to short-term fluctuations. It rises with infections, intense exercise, poor sleep, recent illness, and many other transient states.

If you measure your CRP on a Monday after a hard weekend of training, get an elevated number, then measure again two weeks later after a quiet week and get a normal number, you have not tracked a change in your chronic inflammatory state. You have tracked the noise of acute fluctuation around an unchanged chronic baseline.

The intra-individual coefficient of variation of CRP over short timeframes is substantial - frequently 30–50% in published analytical studies. For a snapshot, that variability is acceptable. For longitudinal tracking of chronic state, it makes interpretation difficult.

The problem with cytokine panels

Direct measurement of inflammatory cytokines (IL-6, TNF-alpha, IL-1) is informative in research but problematic in clinical use. Cytokine levels in blood are very low (often near assay detection limits), highly variable across time, sensitive to sample handling, and influenced by many short-term factors. They are useful in research cohorts; they are difficult to use clinically as longitudinal trackers.

The problem with composite scores

Some products combine multiple inflammation-related markers into a composite "inflammation score." This can be useful - particularly when validated against clinical endpoints - but composite scores inherit the variability of their components. If three of five inputs are noisy, the output is noisy.

What we actually want

For tracking chronic inflammation and inflammaging, we want a biomarker with several specific properties: it should reflect chronic immune activation rather than acute response; it should be analytically stable over short timeframes; it should be modifiable enough to register real biological change in response to intervention; and it should predict the long-term outcomes that inflammaging biologically causes.

04suPAR: a different kind of inflammation marker

Soluble urokinase plasminogen activator receptor - suPAR - is the biomarker that meets the criteria above as well as any single marker we have.

The biology is worth understanding briefly. Cells of the immune system, particularly monocytes and activated lymphocytes, express a membrane-bound receptor called uPAR. When the immune system is activated - chronically or acutely - uPAR is cleaved from the cell surface and released into circulation as the soluble form, suPAR. Higher chronic immune activation produces higher chronic suPAR levels.

What makes suPAR different from CRP and from cytokine panels is its kinetics. suPAR does not spike acutely the way CRP does in response to a single inflammatory event. It reflects an integrated, time-averaged measure of immune activation across days and weeks. This makes it analytically far more stable for chronic tracking - and far more reflective of the inflammaging signal that matters for long-term health.

The published literature on suPAR's clinical performance is now substantial. Over 1,250 published clinical studies (PubMed, May 2026). Over one million tests performed clinically as of January 2024. Twenty-plus years of hospital and emergency department use. The biomarker has been validated as an independent predictor of long-term health outcomes - cardiovascular disease, type 2 diabetes, chronic kidney disease, cancer, cognitive decline, frailty - across cohorts spanning hundreds of thousands of patients.

05What drives your suPAR level

Knowing what your suPAR level reflects gives you a clear picture of what drives it - and what you can do about it. The major modifiable drivers of elevated suPAR, in approximate order of effect size in the literature:

• Smoking. Among the strongest modifiable drivers. Cessation reduces suPAR within months, and the magnitude of reduction is meaningful even in people with decades of smoking history.
• Excess adiposity, particularly visceral adipose tissue. Adipose tissue, particularly visceral fat, is metabolically active and produces inflammatory signals continuously. Weight loss reduces suPAR roughly in proportion to visceral fat loss.
• Heavy alcohol consumption. Alcohol is directly inflammatory at heavy chronic intake and contributes to elevated suPAR. Reduction or cessation improves the marker over months.
• Chronic sleep deprivation. Chronic insufficient sleep (less than 6 hours regularly) is a documented driver of inflammatory markers including suPAR. Sleep optimization protocols can improve the marker.
• Sedentary behavior. Lack of regular physical activity is associated with elevated suPAR. Both aerobic and resistance training interventions have shown reductions.
• Poor dietary patterns. Diets high in ultra-processed food, low in fiber, low in omega-3 intake, and high in refined sugar are associated with elevated inflammatory markers including suPAR. Mediterranean-pattern diets are associated with lower levels.
• Chronic psychological stress. Sustained psychological stress drives elevated systemic inflammation through HPA axis activation. Interventions that address chronic stress can improve inflammatory markers.
• Underlying chronic medical conditions. Type 2 diabetes, chronic kidney disease, autoimmune conditions, and several other chronic diseases elevate suPAR independently of lifestyle. In these cases, suPAR reflects the disease state and supports clinical management.

06Tracking inflammaging with suPAR: the practical use

For someone who actually wants to know whether their chronic inflammatory state is improving over time, the practical approach with suPAR is:

• Establish a baseline. A single measurement that tells you where you stand against population norms for your age and sex. This is the starting point.
• Make changes. Choose one or two of the major drivers above where you have the largest opportunity, and address them consistently for three to six months. Do not try to change everything at once - both because it is not sustainable and because attribution becomes impossible if many things change simultaneously.
• Retest at three to six months. The cadence matters. Less than three months and many interventions have not had time to register their full effect. More than six months and you lose the chance to course-correct.
• Discuss the result with a clinician. A suPAR result is data; clinical interpretation makes it useful. Whether your trajectory is moving in the right direction, whether other tests are warranted, what the next intervention should be - these are clinical questions, not algorithmic ones.
• Repeat. Healthspan optimization is a longitudinal practice, not a one-time event. The value of suPAR is in the trajectory, not the snapshot.

07What we don't know yet

Honesty about a biomarker requires honesty about what is still uncertain.

The literature on suPAR's response to specific interventions is strong for the broad lifestyle domains we have described, but more limited for novel longevity interventions - most of the experimental drugs and protocols currently being explored in the longevity research space. We do not yet know how suPAR responds to NAD+ precursors, rapamycin, senolytics, or other emerging interventions in well-powered intervention trials. That work is ongoing.

We also do not yet know the optimal target range for suPAR in healthspan optimization. Population reference ranges are well-established, but the optimal level for someone actively pursuing healthspan - particularly someone who is already in the healthy range - is an area of active inquiry.

We are open about these uncertainties. The biomarker is the best we have for chronic inflammation tracking, but no biomarker is the end of the story.

08Bottom line

Chronic inflammation, or inflammaging, is one of the central mechanisms linking lifestyle to long-term health and aging. It is real, it is measurable, and it is modifiable.

The traditional clinical marker for inflammation (CRP) is excellent for acute response but limited for tracking chronic state. Cytokine panels are useful in research but problematic for individual longitudinal use. suPAR is, by the criteria that matter for chronic inflammation tracking, the most clinically grounded and analytically robust single-biomarker option available.

If you are serious about understanding and improving your chronic inflammatory state, suPAR is the measurement to anchor your work on.