One systematic review and metanalysis (1), demonstrated a large and significant effect size in favour of reducing anxiety − 0.94 (95% CI: 0.94) with nature based physical activity and found the most effective interventions were offered for between 8 and 12 weeks, and the optimal dose ranged from 20 to 90 min.
The metanalysis has also shown that exercising in nature has a large effect at developing a positive affect and reducing a negative affect.
Quality of evidence
B –some inconsistency demonstrated with high levels of heterogenicity and large CI’s evidence from meta-analysis and systematic review of 5 RCT’s.
Strength of recommendation
1 – significant benefit, low risk of PA.
1) Coventry PA, Brown JE, Pervin J, Brabyn S, Pateman R, Breedvelt J, Gilbody S, Stancliffe R, McEachan R, White PL. Nature-based outdoor activities for mental and physical health: Systematic review and meta-analysis. SSM Popul Health. 2021 Oct 1;16:100934. doi:10.1016/j.ssmph.2021.100934. PMID: 34646931; PMCID:PMC8498096.