Inflammation and Aging: How Chronic Inflammation Shortens Your Life

Acute inflammation is an evolutionarily refined tool: an infection or injury triggers an immune response, tissues recover, and the inflammation subsides. The problem lies elsewhere: with age, most people develop a background low-grade inflammation without an obvious trigger. Claudio Franceschi and colleagues described this phenomenon back in 2000, coining the term inflammaging — a blend of "inflammation" and "aging." Today it is one of the central concepts in gerontology.

What Is Inflammaging and Why Does It Occur

Inflammaging is a chronic, sterile, low-grade inflammation that increases in parallel with biological age. It is not accompanied by the classic signs of inflammation — redness, swelling, pain — and therefore remains invisible in everyday life. But it can be measured in the blood: levels of interleukin-6 (IL-6), C-reactive protein (CRP), and tumor necrosis factor alpha (TNF-α) are systematically higher in older people than in young healthy adults.

The mechanisms of inflammaging are numerous. Key ones include:

• Accumulation of cellular debris: senescent cells secrete pro-inflammatory molecules — the so-called SASP (senescence-associated secretory phenotype).
• Changes in the microbiome: imbalance in the gut microbiome with age alters the intestinal barrier function and triggers chronic immune activation.
• Immunosenescence: dysregulation of the immune system — T-cells lose their ability to effectively control inflammation.
• Chronic antigen exposure: viral infections (e.g., cytomegalovirus) sustain immune activation over the long term.

How IL-6 Is Linked to Disease and Mortality

A meta-analysis by Tylutka, Walas, and Zembron-Lacny (Frontiers in Immunology, 2024) covered 38 studies involving 8,154 elderly patients with diseases and 33,967 controls. The authors found that IL-6 levels were significantly higher in the disease group compared to controls (SMD 0.16; 95% CI 0.12–0.19; p<0.001). Diagnostic odds ratio analysis confirmed the predictive value of IL-6: OR 1.03 (95% CI 1.01–1.05; p=0.0029). Neither TNF-α nor IL-1β showed comparable prognostic power.

A more direct assessment of mortality risk came from the study by Meier and colleagues (GeroScience, 2023), based on the HRS (Health and Retirement Study) cohort — a representative sample of 3,113 Americans over 50 with DNA methylation data. The authors constructed an integrated latent measure of systemic inflammation from seven biomarkers. Result: one standard deviation shift in this measure was associated with a 2.778-fold increase in the odds of death within 4 years — after adjustments for demographic factors and comorbidities. Importantly, inflammation and epigenetic aging (measured by 13 DNA methylation clocks) proved to be independent predictors of mortality — they do not reduce to each other.

What Actually Reduces Chronic Inflammation

Data on modifying inflammaging are accumulating along two lines: physical activity and diet. Of these, the data on exercise are the most systematized.

The meta-analysis by Wang and colleagues (Frontiers in Psychology, 2023) included 38 randomized controlled trials involving 2,557 healthy adults (ages 21–86). Long-term exercise training significantly reduced all three key pro-inflammatory markers:

• IL-6: SMD −0.16 (95% CI −0.30 to −0.03; p=0.017)
• CRP: SMD −0.18 (95% CI −0.31 to −0.06; p=0.005)
• TNF-α: SMD −0.43 (95% CI −0.62 to −0.24; p<0.001)

The optimal protocol according to the analysis: moderate intensity, at least 12 weeks, at least three sessions per week. It is precisely with these parameters that the anti-inflammatory effect was most pronounced. High-intensity training produces a more acute but less stable result.

According to reviews by Franceschi et al. (Nature Reviews Endocrinology, 2018) and several subsequent studies, the Mediterranean diet — rich in fiber, omega-3, polyphenols, and limited in ultra-processed foods — is also associated with reduced inflammation markers in observational studies. However, there are fewer randomized data with mortality endpoints here than for physical activity.

Limitations: What We Still Don't Know

Most inflammaging research is observational or cross-sectional in nature. The causal relationship between IL-6 levels and mortality is convincingly supported by epidemiology, but randomized trials with mortality endpoints in this area are rare. Reducing inflammatory markers through exercise is possible — but whether this reduction translates directly into years of life is something science cannot yet claim with the same confidence as for physical activity in general.