The Effect of Walking on Depressive and Anxiety Symptoms: Systematic Review and Meta-Analysis.

Background: Previous literature lacks summative information on the mental health benefits achieved from different forms of walking. Objective: The aim of this study was to assess the effectiveness of different forms of walking in reducing symptoms of depression and anxiety. Methods: This was a systematic review and meta-analysis of randomized controlled trials (RCTs) assessing the effects of walking on depressive and anxiety symptoms. MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), Embase, PsycINFO, Allied and Complementary Medicine Database (AMED), CINAHL, and Web of Science were searched on April 5, 2022. Two authors independently screened the studies and extracted the data. Random-effects meta-analysis was used to synthesize the data. Results were summarized as standardized mean differences (SMDs) with 95% CIs in forest plots. The risk of bias was assessed by using the Cochrane Risk of Bias tool. Results: This review included 75 RCTs with 8636 participants; 68 studies reported depressive symptoms, 39 reported anxiety symptoms, and 32 reported both as the outcomes. One study reported the results for adolescents and was not included in the meta-analysis. The pooled results for adults indicated that walking could significantly reduce depressive symptoms (RCTs: n=44; SMD -0.591, 95% CI -0.778 to -0.403; I2=84.8%; τ2=0.3008; P<.001) and anxiety symptoms (RCTs: n=26; SMD -0.446, 95% CI -0.628 to -0.265; I2=81.1%; τ2=0.1530; P<.001) when compared with the inactive controls. Walking could significantly reduce depressive or anxiety symptoms in most subgroups, including different walking frequency, duration, location (indoor or outdoor), and format (group or individual) subgroups (all P values were <.05). Adult participants who were depressed (RCTs: n=5; SMD -1.863, 95% CI -2.764 to -0.962; I2=86.4%; τ2=0.8929) and those who were not depressed (RCTs: n=39; SMD -0.442, 95% CI -0.604 to -0.280; I2=77.5%; τ2=0.1742) could benefit from walking effects on their depressive symptoms, and participants who were depressed could benefit more (P=.002). In addition, there was no significant difference between walking and active controls in reducing depressive symptoms (RCTs: n=17; SMD -0.126, 95% CI -0.343 to 0.092; I2=58%; τ2=0.1058; P=.26) and anxiety symptoms (14 RCTs, SMD -0.053, 95% CI -0.311 to 0.206, I2=67.7%, τ2=0.1421; P=.69). Conclusions: Various forms of walking can be effective in reducing symptoms of depression and anxiety, and the effects of walking are comparable to active controls. Walking can be adopted as an evidence-based intervention for reducing depression and anxiety. More evidence on the effect of low-intensity walking is needed in the future.