Effects of Water-Based Aerobic Exercises on Physical Fitness in Older Adults: A Systematic Review With Meta-Analysis of Randomized and Nonrandomized Trials

OBJECTIVES: To investigate the effects of water-based aerobic exercises on the physical fitness of older adults. METHODS: PubMed, LILACS, and EMBASE were searched in April 2024. Eligibility criteria included randomized and nonrandomized trials focused on water-based aerobic exercise programs for older adults assessing physical fitness. Random-effects meta-analyses were conducted to compare water-based aerobic exercise programs with (a) control groups, (b) land-based aerobic exercise, and (c) water-based combined exercises. Mean difference (MD) and standardized mean difference (SMD), with a 95% confidence interval (CI), were used for studies with the same measurement scale and different scales, respectively. The methodological quality of the studies was assessed using the Tool for the Assessment of Study Quality and Reporting in Exercise (TESTEX). RESULTS: Fifteen studies were included in the meta-analyses. Water-based aerobic exercises significantly improved cardiorespiratory capacity (MD = 5.18 ml·kg-1·min-1; 95% CI [2.51, 7.85]; I2 = 91%), muscle strength (MD = 3.03 kg; 95% CI [1.62, 4.44]; I2 = 11%), and agility/dynamic balance (SMD = 0.63; 95% CI [0.11, 1.16]; I2 = 77%) compared to control groups. The significant effect favoring aquatic aerobic exercise for agility/dynamic balance was observed only in nonrandomized clinical trials. Cardiorespiratory capacity improvements were similar between water- and land-based aerobic exercise programs (MD = 3.23 ml·kg-1·min-1; 95% CI [-2.45, 8.91]; I2 = 91%). Additionally, water-based aerobic exercise was superior to water-based combined exercise programs in improving cardiorespiratory capacity (SMD = 0.58; 95% CI [0.15, 1.01]; I2 = 36%), while muscle strength (SMD = -0.04; 95% CI [-0.38, 0.30]; I2 = 0%) and agility/dynamic balance (SMD = 0.17; 95% CI [-0.18, 0.51]; I2 = 0%) were similar. The quality of included studies ranged from 6 to 13 points on the TESTEX scale. CONCLUSION: Besides improved cardiorespiratory fitness, water-based aerobic exercise programs promote increased muscle strength and agility/dynamic balance in older adults.