Effectiveness of Aquatic Exercise in the Management of Fibromyalgia Syndrome: A Systematic Review and Meta-Analysis

Background/Objectives: Fibromyalgia syndrome (FMS) is a chronic condition characterized by widespread pain, fatigue, sleep disturbances, and psychological symptoms. Aquatic exercise offers the benefits of physical activity with reduced mechanical stress. This meta-analysis evaluated the effectiveness of AE on pain, functional physical status, and health-related quality of life. Methods: A PRISMA-guided systematic review and meta-analysis (PROSPERO CRD42025115158) included randomized and non-randomized trials up to October 2025 from MEDLINE (PubMed), Cochrane Library, PEDro, CINAHL Complete, SPORTDiscus, and Academic Search Ultimate. Eligible participants were adults diagnosed with FMS undergoing AE programs, alone or combined with other modalities. Standardized mean differences (SMD) with 95% confidence intervals were pooled using random- or fixed-effects models. Methodological quality, risk of bias, and certainty of evidence were evaluated using the PEDro scale, the RoB 2.0 tool, and the GRADE approach. Results: 27 trials (n = 1785; >95% women; mean age 44–62 years) were included. AE significantly improved pain (SMD = −0.92; 95% CI: −1.03 to −0.80; p < 0.00001), physical function (SMD = −0.74; 95% CI: −0.84 to −0.63; p < 0.00001), and HRQoL (SMD = 0.57; 95% CI: 0.42 to 0.72; p < 0.00001). Effects were consistent across time frames, though overall heterogeneity was considerable (Tau2 = 4.93; I2 = 97%). The mean PEDro score was 5.2/10, and RoB 2.0 indicated moderate methodological limitations mainly due to a lack of blinding. Evidence certainty was low for the main outcomes and moderate for adverse events. Conclusions: Aquatic exercise is an effective and safe complementary therapy for patients with FMS, alleviating pain while enhancing function and quality of life. However, methodological variability and small sample sizes warrant further high-quality trials to confirm these findings and explore underlying mechanisms.