Abstract There is an increasing evidence that natural environment provides substantial human health benefits. One mechanism underlying this relationship is the experience of stress. However, no formal statistical assessment has been conducted to test this statement. A meta-analysis was used in our study to conduct a comprehensive systematic review for the effect of direct exposure to natural environment on stress relieving. We searched four online databases and reference lists, 31 studies with a total of 1842 participants were included. Meta-analysis results showed increased natural exposure was associated with decreased salivary cortisol -0.06 (95% CI -0.08, -0.04), state-of anxiety -12.48 (95%CI -26.61, 1.66), self-reported stress -0.33 (95%CI -0.78, 0.13), systolic blood pressure (SBP) -3.82 (95%CI -6.77, -0.86), diastolic blood pressure (DBP) -2.21 (95%CI -3.93, -0.49), Ln(LF/HF) -0.29 (95%CI -0.41, -0.18) of heart rate variability (HRV) and increased restorative outcomes 4.82 (95%CI -1.87, 11.51). These measurements provide the most convincing evidence that exposure to the natural environment can lead to stress reduction, and ultimately improve health. However, there was significant residual heterogeneity between studies and risk of bias was high. It is a recommended that future research in this area take appropriate steps to reduce bias and improve quality in order to build a strong evidence-based medicine foundation. This will help to convince policymakers and health professionals of the stress relieving benefits of exposure to nature, and encourage to give due regard to create, maintain, and improve existing accessible greenspaces in insufficient areas.

中文翻译：

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暴露于自然环境对减压的影响：荟萃分析

摘要 越来越多的证据表明，自然环境为人类健康提供了巨大的好处。这种关系背后的一个机制是压力体验。然而，没有进行正式的统计评估来检验这一说法。我们的研究中使用了一项荟萃分析，对直接暴露于自然环境对缓解压力的影响进行了全面的系统评价。我们检索了四个在线数据库和参考文献列表，纳入了 31 项研究，共有 1842 名参与者。荟萃分析结果显示，自然暴露增加与唾液皮质醇降低相关 -0.06 (95% CI -0.08, -0.04)，焦虑状态 -12.48 (95% CI -26.61, 1.66)，自我报告压力 -0.33 ( 95%CI -0.78, 0.13), 收缩压 (SBP) -3.82 (95%CI -6.77, -0.86), 舒张压 (DBP) -2.21 (95%CI -3.93, -0.49), Ln(LF/HF) -0.29 (95%CI -0.41, -0.18) 心率变异性 (HRV) 和恢复性结果增加 4.82 ( 95% CI -1.87, 11.51)。这些测量提供了最令人信服的证据，证明暴露于自然环境可以减少压力，并最终改善健康。然而，研究之间存在显着的残余异质性，偏倚风险很高。建议该领域的未来研究采取适当措施减少偏倚并提高质量，以建立强大的循证医学基础。这将有助于让决策者和卫生专业人员相信接触自然的缓解压力的好处，并鼓励适当考虑创造、维持、