Exercise cools inflammation in over-65s, but only some markers move

Exercise is one of the best-supported tools for ageing well: it improves functional capacity, cognition and quality of life in older adults. What remains far less clear is how it works at the molecular level, and chronic low-grade inflammation and oxidative stress are two of the leading suspects in the biology of ageing. If structured training genuinely shifts the blood markers of these processes, that would help explain why active older people tend to fare better and would sharpen the case for exercise as a biological intervention, not just a functional one. This review set out to pull together everything the trial literature can currently say on that question.

The authors ran a systematic review and meta-analysis of randomised controlled trials in people aged 65 and over, searching PubMed, Scopus, Web of Science, CINAHL and the Cochrane Library. They identified 50 reports covering 4,379 participants for the qualitative synthesis, of which 38 fed into the pooled statistical analyses. The exercise interventions were supervised and structured, lasting anywhere from 8 weeks to 12 months, and spanned aerobic training, resistance training and multicomponent programmes. The outcomes were blood biomarkers of inflammation, such as C-reactive protein and various cytokines, and markers of oxidative stress.

The headline result was a modest but statistically significant reduction in C-reactive protein and high-sensitivity C-reactive protein after exercise, alongside an increase in IL-10, a cytokine with anti-inflammatory actions. The picture was not uniform: effects on other pro-inflammatory cytokines, including IL-6 and TNF-α, were inconsistent across the included studies, so exercise did not reliably move every marker in the panel. A smaller body of evidence, just 6 trials, also suggested improvements in redox balance, hinting at an antioxidant effect. The authors judged the overall risk of bias in the underlying trials to be moderate to high, which tempers confidence in the precise effect sizes.

This review strengthens the long-standing idea that exercise is immunomodulatory, and it does so with the most rigorous design available: pooled randomised trials rather than comparisons of active and inactive people. At the same time, it complicates simpler narratives, because the anti-inflammatory effect showed up in some markers and not others. Open questions remain about which type, dose and duration of exercise matters most, whether the biomarker shifts are large enough to be biologically meaningful, and whether they translate into fewer diseases or longer life. The thin evidence on oxidative stress, from only 6 trials, is an obvious gap for future work.

For anyone thinking about training into later life, this is a reason to believe regular structured exercise does more than build strength and stamina: it appears to nudge the body's inflammatory profile in a favourable direction. The honest sizing matters, though. The changes were modest, some markers did not move consistently, and the underlying trials had quality problems, so this is supportive evidence rather than proof of a powerful anti-inflammatory effect. It fits a picture in which exercise acts as slow, cumulative maintenance on ageing biology rather than a quick fix you could measure in a single blood test.