The effects of water-based exercise on body composition: A systematic review and meta-analysis

Aims: This study aimed to investigate the effects of water-based exercise (WBE) on body composition.Methods: Trials published up to October 28, 2022 were searched using the PubMed, EMBASE, Web of Science, Cochrane, Scopus, and Ovid databases. Randomized controlled trials of healthy adults published in English, comparing WBE and control groups, were included. Other studies with different research designs and participants with medical diagnoses were excluded. The main outcome measures were body weight (BW), body fat mass (BFM), body fat percentage (BFP), lean mass (LM), and skeletal muscle mass (SMM).Results: Overall, 17,458 potential studies were identified. After a closer inspection, 79 full-length articles were considered for further screening. Finally, 20 studies, involving 565 participants, were included in the metaanalysis. The WBE was beneficial in reducing BW, BFM, and BFP and increasing LM and SMM. Subgroup analyses were conducted based on different exercise intensities and times per week. Moderate- or moderatevigorous-intensity exercise helped improve body composition, while lower-intensity WBE or aquatic highintensity interval training (HIIT) seemed less helpful. Training for <120 min/week was insufficient to improve body composition. Training for >120 min/week was associated with improvements in body composition.Conclusions: Moderate- or moderate-vigorous-intensity WBE helps improve body composition. Adults are encouraged to exercise for >120 min/week.