Background: Exercise is a central regulator of metabolic and neurotrophic processes, in which irisin and brain-derived neurotrophic factor (BDNF) play key roles in mediating muscle–brain communication. Objective: This systematic review aimed to summarize the effects of different exercise modalities and immobilization on irisin and BDNF expression, focusing on the PGC-1alpha–FNDC5–irisin signaling pathway. Methods: The review followed the PRISMA 2020 guidelines. Studies published between January 1995 and September 2025 were identified through PubMed, Scopus, Web of Science, and Google Scholar using Boolean search combinations (‘irisin’ AND ‘BDNF’ AND ‘exercise’). Inclusion criteria covered human and animal studies exploring the irisin–BDNF axis. Data were extracted independently and synthesized qualitatively. Risk of bias was assessed using Cochrane domains. Results: Evidence indicates endurance, resistance, and high-intensity interval training increase circulating irisin and hippocampal BDNF levels. Acute exercise induces transient increases, whereas chronic training produces sustained adaptations. Immobilization reduces both irisin and BDNF expression. Conclusions: Current evidence suggests the PGC-1alpha–FNDC5–irisin–BDNF axis may constitute a molecular link between skeletal muscle activity and brain health; causal conclusions are limited by the associative and largely preclinical nature of the evidence. This review was not prospectively registered. Methodological heterogeneity precluded meta-analysis. Data extraction sheets and full search strings are available as supplementary material.
E. M. Ersever· Muscles Ligaments and Tendon...· 0 citations
Age-related cognitive decline is closely associated with diminished neuroplasticity and disrupted neurotrophic signaling. Exercise is a potent modulator of the irisin-BDNF axis, a molecular pathway with emerging relevance to healthy aging, neuroprotection, and the prevention of neurodegenerative diseases in older adults. Through this analysys the author aimed to review evidence on the effects of different exercise modalities - with emphasis on aging populations - on the PGC-1α-FNDC5-irisin-BDNF signaling pathway, and to examine implications for cognitive health and neuroplastic adaptations across the lifespan. A structured, reproducible search of PubMed, Scopus, Web of Science, and Google Scholar was conducted for studies published between January 1995 and September 2025, using Boolean combinations of 'irisin', 'BDNF', 'exercise', 'aging', 'neuroplasticity', and 'cognitive function'. Human and animal studies exploring the irisin-BDNF axis in the context of aging, physical activity, or immobilization were eligible. Data were extracted and synthesized qualitatively. Consistent with the narrative design, no formal risk-of-bias instrument or PRISMA systematic-review reporting framework was applied, and the review was not prospectively registered. Twenty-four studies met inclusion criteria. Resistance and High-Intensity Interval Training (HIIT) consistently increased circulating irisin and hippocampal BDNF levels. Aging-related declines in both biomarkers were attenuated by chronic resistance training, particularly in older adults. Immobilization suppressed the irisin-BDNF pathway. Epigenetic modifications at BDNF promoters represent a plausible mechanism for sustained neuroplastic adaptations. The PGC-1α-FNDC5-irisin-BDNF axis may constitute a key molecular link between skeletal muscle activity and brain health in aging populations. Resistance training and HIIT offer the most consistent evidence for attenuating age-related neurotrophic decline, although HIIT-specific data in older adults remain limited and warrant cautious interpretation. Causal conclusions remain premature given the predominantly associative and preclinical evidence base. Well-powered, longitudinal prospective trials in older adults with standardized biomarker protocols are needed.
E. M. Ersever· European Journal of Translat...· 0 citations
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