Green exercise and nature-based physical activity among university students: a systematic review and exploratory meta-analysis of psychological outcomes and experiences

Background University students face psychological demands, and green exercise or nature-based physical activity may support mental health. This review examined psychological outcomes and experiences among university students. Methods Following PRISMA 2020, the protocol was prospectively registered in PROSPERO (CRD420261444510). Web of Science, Scopus, PubMed, and ERIC were searched on 8 July 2026 without publication-year restrictions, and reference lists were screened. Eligible qualitative, quantitative, and mixed-methods studies examined physical activity in natural, green, blue, or other eligible outdoor settings and reported psychological outcomes among university or college students. Methodological quality was appraised using the Mixed Methods Appraisal Tool, risk of bias was assessed using design-specific tools, and certainty of evidence was evaluated using the GRADE framework for the two meta-analyzed outcomes. Narrative synthesis was the primary approach; sufficiently comparable controlled data were pooled in exploratory random-effects meta-analyses using restricted maximum likelihood estimation, with Hartung–Knapp sensitivity analyses. Results Thirty-five reports representing 34 independent samples from 14 countries or regions were included. Two independent studies contributed to each exploratory meta-analysis. The conventional pooled estimate favored green exercise or nature-based physical activity for perceived stress [Hedges' g = 0.51, 95% CI (0.20, 0.82); I 2 = 0.0%], but the Hartung–Knapp interval crossed the null [95% CI (−0.66, 1.67)]. The anxiety estimate was inconclusive [ g = 0.43, 95% CI (−0.31, 1.16); I 2 = 74.3%] and remained uncertain in sensitivity analysis. Certainty of evidence was very low for both perceived stress and anxiety. Narrative findings suggested benefits for stress, negative mood, fatigue, restoration, self-esteem, and nature connectedness, whereas findings for depression, trait anxiety, positive affect, loneliness, mental wellbeing, and burnout-related outcomes were null or mixed. Qualitative findings highlighted restoration, present-moment awareness, nature connection, meaningful challenge, and social participation, with experiences shaped by safety, accessibility, and context. Conclusion Green exercise and nature-based physical activity may support aspects of students' psychological wellbeing, particularly stress, mood, fatigue, and restoration. However, findings were clearer against inactive than active comparators, leaving the additional contribution of natural settings uncertain. Evidence was heterogeneous and limited, and pooled estimates were based on very few studies. Controlled studies separating physical-activity and environmental effects are needed. Systematic review registration https://www.crd.york.ac.uk/PROSPERO/view/CRD420261444510 , identifier: CRD420261444510.