Exercise-Induced Regulation of Spexin: Implications for Metabolic Health: A Systematic Review and Meta-Analysis

Background/Objectives: Spexin (SPX) is a bioactive peptide involved in the regulation of appetite, lipid metabolism, and glucose homeostasis. This systematic review and meta-analysis aimed to evaluate exercise-induced changes in SPX levels and their implications for metabolic health. Methods: This systematic review and meta-analysis aimed to synthesize evidence retrieved from PubMed, Web of Science, and Scopus databases, without restrictions on publication year, with the final literature search completed on 10 September 2024 and conducted in line with PRISMA 2020 reporting standards. The search strategy employed the keywords exercise, metabolic health, obesity, spexin and diabetes yielding 42 eligible records. Eligible studies included human or experimental animal populations exposed to acute or chronic exercise interventions. Exercise interventions included aerobic, resistance, combined, and high-intensity interval training protocols, with exercise intensity reported using heterogeneous metrics. The primary focus was on circulating SPX, alongside the assessment of related metabolic and endocrine parameters. Six studies satisfied the eligibility criteria and were included in the review. Results: The included studies were conducted in overweight or obese sedentary populations. Plasma SPX levels remained unchanged following acute (<3 weeks) aerobic exercise, whereas increased SPX levels were reported after chronic (≥3 weeks) exercise interventions. Elevated SPX concentrations were observed across different exercise modalities, including aerobic exercise, combined aerobic-resistance training, treadmill running, swimming, and HIIT. In addition to SPX, the included studies reported changes in metabolic and endocrine markers, including lipid-related variables, insulin-associated indices, adipokines, hormones, and selected metabolic proteins. Conclusions: This systematic review and meta-analysis indicate that exercise-related increases SPX are reported alongside changes in adiposity and metabolic-endocrine markers.