Acute autonomic and cardiovascular responses to walking in natural versus urban environments: A systematic review and three-level meta-analysis

Acute physiological responses to walking in natural versus urban environments remain uncertain. We reviewed studies of healthy adults completing single walks in actual outdoor settings. Six databases were searched through January 12, 2026, and reporting followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses framework. We included 21 studies; 20 contributed 57 effect estimates to a three-level meta-analysis. Pooled Hedges' g estimates with 95% confidence intervals were -0.01 [-0.26, 0.23] for heart rate (p = 0.90), 0.11 [-0.40, 0.62] for systolic blood pressure (p = 0.63), and -0.14 [-0.36, 0.08] for diastolic blood pressure (p = 0.18). Evidence was inconclusive for high frequency heart rate variability (g = -0.14 [-0.94, 0.66], p = 0.66) and the root mean square of successive differences between normal interbeat intervals (g = -0.01 [-0.89, 0.87], p = 0.98), with few estimates and wide intervals. Exploratory analyses found no clear moderating associations with walking duration or study sample sex composition, although small subgroups limited precision. Overall, current evidence does not show a consistent additional acute physiological response to natural walking. This does not establish equivalence or rule out true differences. Estimates reflect heterogeneous routes and protocols and cannot isolate a uniform causal effect of nature exposure. Psychological restoration, sustained physical activity, disease prevention, and clinical outcomes require separate evidence. Future studies should better characterize environmental exposures and standardize walking and measurement procedures.