The effects of a nature walking intervention on the mental health of university students: A pragmatic randomized-controlled study

Background This pragmatic randomized controlled study examined the effects of a 4-week nature walk (vs. urban walk) intervention on university students’ mental health, a population known to experience high rates of psychological symptoms. Method Using a parallel group design, university students were randomized to complete 2-3 weekly walks over 4 weeks in either an urban greenspace (nature condition) or city streets (urban condition). Assessments were completed online at pre-randomization/baseline, weekly (primary outcomes only), and post-intervention. The primary outcomes were positive and negative affect, with depressive and anxiety symptoms as secondary outcomes. Trial registration: NCT05889078. Mixed model analyses (adjusting for baseline measures) adhered to intent-to-treat principles. Results Ninety-three participants (47 in nature, 46 in urban) received the intervention. Participants were mostly female (87%; M age =20.61 years; SD =1.94). Mixed model analyses revealed no effect of the nature walks on positive and negative affect, nor on depressive and anxiety symptoms. Post-hoc moderation analyses revealed greater reductions in depressive symptoms for the nature (vs urban) condition, but only in participants with higher baseline depressive symptoms ( p for interaction=.04). To illustrate, for students with baseline symptoms in the moderately-severe-to-severe range, the mean difference in depressive symptoms at post-intervention was -3.86 (95% CI: -7.38 to -0.33), with a large effect size ( d =0.85). Limitations The small sample size and higher number of female participants limit the generalizability of results. Conclusions Although this study did not provide evidence that nature walks improve mental health for all university students, benefits were observed for reducing depressive symptoms for those with higher baseline symptoms.