Sex Differences in Effects of Exercise on Physical Function in Aging: A Systematic Review with Meta-Analysis

Purpose: Our objective was to synthesize and determine whether there are sex differences in physical function following exercise interventions in older adults. Materials and Methods: A systematic search was conducted in four databases from inception to July 8th, 2023 searching for prospective trials that conducted exercise interventions in older adults and results for physical function were reported by sex. Pooled standardized mean differences (SMDs) with their 95% confidence intervals (CIs) were estimated using a randomeffects method. The Sidik-Jonkman estimator was used to calculate the variance of heterogeneity (I2). Results: A total of 19 studies involving 20,133 older adults (mean age >= 60 years, 33.7% female) were included. After exercise interventions, males reported significantly greater pre-post changes compared to females for upper body strength (SMD=0.40, 95% CI: -0.71 to -0.09; I2=75.6%; n=8), lower body strength (SMD=-0.32, 95% CI: -0.55 to -0.10; I2=52.0%; n=11), and cardiorespiratory fitness (SMD=-0.29, 95% CI: -0.48 to -0.10; I2=89.1%; n=12). Conversely, the pooled SMDs showed a significant effect favoring females for motor fitness (SMD=0.21, 95% CI: 0.03 to 0.39; I2=0%; n=7). Limited and inconsistent results were observed for flexibility. Conclusions: Our study suggests the existence of sex-related differences on physical function after an exercise intervention in the older population.