Research suggests that exposure to natural environments can be beneficial for health, such as reducing physical illness and improving mood and cognitive ability. The potential benefits of nature have come into focus at a time when mental health issues are growing globally. Here, we have selected 24 studies from four databases for meta-analysis to explore the effects of exposure to the natural environment on the anxiety of the human body and summarize the influencing factors on the anxiety relief effect. A random-effect meta-analysis of anxiety state changes before and after exposure to natural environment shows that natural exposure effectively alleviated human anxiety (SMD −1.28, 95% CI: −1.65 to −0.92). The overall quality of the included papers, assessed using the PEDro scale, is considered to vary considerably, but most of the papers are rated between 4 and 7 which is considered fair or good. In addition, we have also investigated the potential moderators of anxiety-relieving effects of the nature. Our results shows that the age and exposure time of the subjects are related to the effect of anxiety relief. The results of the subgroup analysis of moderators prove that compared with the middle-aged people (SMD −0.63, 95% CI: −1.13 to −0.12), young people (SMD −1.50, 95% CI: −1.90 to −1.10) get better anxiety alleviation effect in the natural environment. In terms of exposure time, compared with 0.5–2 h (SMD −0.18, 95% CI: −0.59 to −0.23) and >2 h (SMD −0.84, 95% CI: −1.40 to −0.27) exposure periods, subjects get the maximum anxiety relief benefit when they spent <0.5 h (SMD −1.60, 95% CI: −1.93 to −1.27) in the natural environment. However, the quality of the included studies varies greatly and there is a significant heterogeneity in the meta-analysis. Study location, natural environment type and other moderator factors have no obvious correlation with anxiety-alleviation effect of the nature. A higher quality and more comprehensive study needs to be carried out to find out more moderators about the effects of the natural environment on anxiety alleviation. Further experimental studies should also be conducted to determine the mechanism by which natural exposure reduces anxiety so as to provide strong support for the construction and improvement of healthy natural environment.

With the development of the urban park, people's cognition of the relationship between the environment and public health has been improved, and higher requirements for the living environment have been put forward. As an important group of park users, youths often have different needs regarding the health benefits brought by urban parks. To explore the potential relationship among youth's satisfaction with urban parks, their usage behavior, and health benefit perception, this article presents some constructive suggestions for the development of healthy landscapes in urban parks. Researchers have selected five typical urban parks from different areas in Qingdao, China. Furthermore, we have used the survey method by combining the practices of “issuing questionnaires, observing and interviewing” with the goal of collecting data on 500 park visitors in autumn, including information on social demography, the satisfaction of park landscape variables, and usage behavior and health perception. A linear regression model has been used to analyze the correlation among “landscape variables,” “usage behavior,” and “health benefit perception.” Results have shown that urban green landscapes and waterscapes can significantly affect youth's social health perception and static behavior. Moreover, static behaviors such as relaxation have a great impact on mental health perception. The results of this study will be beneficial in understanding youth's needs for landscapes when using urban parks. In addition, it will provide insight for the urban planners and landscape designers to design urban parks from the perspective of youth.

Given the current aging population, the demand on medical facilities, facilities for elderly care, and even their high prevalence, it is crucial to investigate the advantages of older people. The amount of scholarly literature examining natural factor-related activities to enhance older people’s health status has steadily risen over the last few decades. But the scope of the present review is limited. We compiled the results of 33 peer-reviewed publications and conducted a meta-analysis using a total of 27 relevant variables to assess the advantages of horticultural therapy (HT) for, among other things, the physical and psychological functioning of the elderly. Results show that horticultural therapy may be helpful in helping seniors lose weight -0.195 (95% CI -0.507,0.117), reduce their waist circumference -0.327 (95% CI -0.637, -0.017), improve their physical flexibility (chair sit-and-reach) 0.302 (95% CI 0.036, 0.569), lower their stress -0.339 (95% CI -0.610, -0.069) and cortisol -0.902 (95% CI -0.728, -0.002) levels, improve social interaction 0.370, (95% CI 0.115, 0.624), increase daily vegetables and fruit consumption 0.688 (95% CI: 0.287, 1.089). HT may be a useful tool for enhancing the physical, mental and social aspects of older adults.