Exercise-induced inflammatory and metabolic adaptations in ageing: A meta-analytic compendium

The relationship between metabolic and inflammatory adaptations with exercise training is poorly quantified. We employed a novel meta-analytical approach to provide an evidence-based framework to guide exercise prescription for health in older adults.

This systematic review (PROSPERO: CRD42025630662) identified controlled exercise training interventions in older adults. We meta-analysed 146 studies assessing body mass, BMI, fat mass, muscle mass, circulating CRP, IL-6, TNF-α, adiponectin, leptin, IGF-1, IL-1β, fasting glucose, insulin, glycated haemoglobin, HOMA-IR, TG, total cholesterol, LDL-C, HDL-C, and VO₂ max. Our novel analytical approach divided studies into "improved" or "not improved" for each variable based on the significant direction of their standardised mean difference (95 % CI), followed by a cross-over subgroup analysis.

Meta-analyses showed that exercise training improved all outcomes, except for IL-1β. Aerobic training showed the greatest overall benefits-except for IGF-1-while resistance training improved most markers but did not reduce body mass and IL-6. A frequency of at least 3 sessions per week was necessary to reduce body mass, insulin, HOMA-IR, triglycerides, total cholesterol, IL-6, TNF-α, leptin, and to increase adiponectin and IGF-1. Shorter interventions (< 12 weeks) led to greater increases in adiponectin and IGF-1 and stronger reductions in TNF-α and IL-1β, suggesting a transient response. Women, unhealthy individuals, and those who were overweight or obese exhibited greater improvements than their counterparts. Anti-inflammatory effects were more pronounced when accompanied by decreases in body mass, fat mass, and improved glucose and lipid metabolism, but was not dependent on those changes.

Aerobic training is the most effective intervention, followed by resistance training, and at least 3 sessions per week (or twice a week for more than 24 weeks) are needed for metabolic and anti-inflammatory adaptations. This compendium provides a reference point for personalised exercise plans for treatment and prevention of chronic diseases-especially for older adults with metabolic conditions.