The science

The Library

The practices at Halcyon are old. The research on them is newer, and growing. These are the studies we read and return to, each with a short note in plain language and a link to the original paper. We share them to inform, not to promise, and none of it is medical advice.

3 studies

Nature immersion · Guided Hike

Nature experience reduces rumination and subgenual prefrontal cortex activation

Bratman GN, Hamilton JP, Hahn KS, et al.

Proceedings of the National Academy of Sciences · 2015

Rumination, the habit of repetitive negative thinking about oneself, is linked to higher risk of depression. In this study published in PNAS, healthy participants took a 90-minute walk either in a natural setting or in an urban setting. Those who walked in nature showed reduced self-reported rumination and reduced activity in the subgenual prefrontal cortex, a brain area associated with rumination, as measured by brain imaging. Those who walked along a busy urban route showed no such changes. The authors suggest this may be one pathway by which nature experience supports mental well-being, and that accessible natural areas could be an important mental health resource. One limitation is that the abstract does not report a large sample, and the participants were healthy adults, so the effect in people with depression is not tested here.

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Nature immersion · Guided Hike

Shinrin-Yoku (Forest Bathing) and Nature Therapy: A State-of-the-Art Review

Hansen MM, Jones R, Tocchini K

International Journal of Environmental Research and Public Health · 2017

Shinrin-yoku, or forest bathing, is the Japanese practice of spending mindful time among trees. This state-of-the-art review set out to gather empirical research on its physical and psychological effects, much of it from Japan and China, and to encourage longitudinal research in Western countries. Searching five databases, the authors started with 127 papers and included 64 studies published between 2007 and 2017, grouping them into physiological, psychological, sensory and framework studies. They conclude that the human health benefits of immersion in nature continue to be actively researched and suggest nature therapy as a possible health promotion approach for modern stress, including technology-related stress. The limitation is that this is a narrative review: it summarizes research but does not pool results or rate how strong each study was.

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Nature immersion · Guided Hike

Spending at least 120 minutes a week in nature is associated with good health and wellbeing

White MP, Alcock I, Grellier J, et al.

Scientific Reports · 2019

Using a nationally representative survey of 19,806 people in England, researchers examined whether the amount of recreational time spent in nature during the previous week was linked to self-reported health and well-being. Compared with people who had no nature contact that week, those who spent at least 120 minutes in nature were significantly more likely to report good health and high well-being. Benefits peaked at around 200 to 300 minutes a week, with no further gain beyond that. The pattern held across groups, including older adults and people with long-term health conditions, and it did not matter whether the time came from one long visit or several shorter ones. The key limitation is that this was a cross-sectional survey, so it shows an association, not that nature time caused better health.

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