Researchers wanted to investigate the impact of forest bathing (Shinrin-yoku) on salivary cortisol levels (a biological marker of stress) in urban-dwelling working adults.
They conducted a meta-analysis on studies published between 2010 and 2023 involving adults aged 25–60 years old, looking at how structured immersion in forested environments compared to urban walking affected post-activity salivary cortisol concentration.
The researchers searched global databases and included studies comparing green space immersion to active urban control groups (such as walking along busy metropolitan streets). They excluded studies involving children, indoor virtual reality nature simulations, and clinical populations with diagnosed endocrine disorders.
Their final analysis included 18 studies on outdoor forest immersion and 8 studies on urban walking controls.
The researchers reviewed two main methodological approaches in the gathered literature:
For the experimental evidence, the meta-analysis found that forest bathing reduced post-intervention salivary cortisol levels by an average of 0.12 mcg/dL compared to urban walking. In the non-experimental evidence, there was a significant negative correlation between self-reported nature exposure frequency and chronic stress scores.
The study concluded that forest bathing significantly reduces physiological stress in urban working adults.
Explain one weakness of using a meta-analysis for the nature exposure and urban stress regulation study.
638 exam-style questions on Edexcel A Level Psychology Methods. Each one has a worked solution and a mark scheme showing where the marks go.