Front cover of Yannick Klein's dissertation (detail).

Poor mental health is one of the leading causes of ill health in Sweden and other countries, making it important to identify affordable and accessible resources to promote mental health and well-being. 

– Nature can be one such resource, provided that it is widely available and easily accessible. With the ongoing urbanization, it is important to understand how nature exposure relates to mental health, says Yannick Klein.

Yannick Klein defended his doctoral thesis entitled “The role of nature exposure for mental health outcomes: Population-based studies of adults in Sweden, before and during the COVID-19 pandemic” on 13 September 2024.

Active and passive exposure to nature

In his research, Yannick Klein looks at how different types of outdoor exposure are linked to mental health. Visiting a forest or park is an example of active behavior and mobility-related type of nature exposure. Simply living near vegetation or water, on the other hand, provides a more passive and automatic exposure to nature, which doesn’t depend so much on mobility.

The three different studies of the dissertation showed that both active and passive exposure to nature were consistently associated with better mental health.

– This was true both before and during the COVID-19 pandemic. While the statistical effects in the models are often small, they appear consistently across different samples, types of exposure, and mental health outcome variables.

This emphasizes that even small statistical effects can have practical relevance if many people can benefit across multiple contexts, including a pandemic.

Having access to nature helped during the pandemic

For some population groups, challenges during the pandemic included the risk of experiencing social isolation, loneliness and mental health symptoms. In Sweden, natural environments such as forests and parks remained accessible throughout the pandemic and were popular spaces for recreational and social activities.

– Given the many studies, including ours, that have found positive associations between various types of nature exposure and mental well-being before the pandemic, it was reasonable to assume that nature exposure could serve as an important resilience factor during the pandemic.

Yannick Klein and his colleagues found it interesting to investigate, in a Swedish population-based sample, whether nature exposure was actually associated with better mental health during COVID-19 – which they found it was.

Landscape planning for improved mental health and climate adaption 

Pandemic times or not, effectively integrating nature into city environments is benefiting the mental health and well-being of many, according to Yannick Klein. He hopes that this knowledge will encourage policies in urban and landscape planning and public health policies to preserve and further develop natural environments when possible. 

– The availability and accessibility of nature can contribute to promoting public mental health and resilience. When carefully planned, health-promoting nature-based solutions can also provide other ecosystem services that are important for improving climate change mitigation and adaptation.

Keeping a strong connection to nature is important

Yannick Klein’s own relationship with nature and green and green-blue environments goes a long way back. Yannick Klein grew up with a very good access to nature. His parents often took him and his brothers to the forest in everyday life and they went camping on holidays. 

Yannick Klein.

– My connection to nature has always been strong, though I didn’t fully realize what that meant and kind of took it for granted. It wasn’t until I left my small hometown in Germany and moved to Paris after high school that I truly felt the absence of nature for the first time.

Working on the different studies of the subject and the dissertation during the past few years has made him aware of how much he actually values and appreciates nature.

– Being able to integrate nature into my daily routines, even in small ways, is important to my perceived quality of life, says Yannick Klein.

Brief interactions with nature can be associated with feeling good and less stressed

What level of nature exposure is enough to feel good?

– It is difficult to give a one-size-fits-all answer. The ideal dose of nature exposure likely depends on a person's baseline mental health, individual needs, and preferences. However, research increasingly shows that even brief interactions with nature, such as a short walk in a park, be near plants, even indoors, or simply viewing nature virtually, can be associated with feeling good and less stressed. Especially if brief exposure happens repeatedly and on a daily basis, there may be potential for a multiplicative effect. 

What are your thoughts on public digital exposure to nature?

– We can see this being used in practice in many places in Stockholm. For example, when you get off the pendeltåg at Odenplan and take the escalator to go up, you will pass by many screens that show a video filmed from a cable car in the Swedish mountains. The experience on the escalator creates a sense of slowly riding along in the green late summer landscape without reaching any destination. Initiatives like this have my full support! They are small ways to integrate nature into daily life in a repetitive way.

How do you get exposure to nature yourself – do you practice what you preach? 

– Yes, I do. Especially during the winter months, I try to catch some daylight by cycling to work, and taking little walks in the forest or to Brunnsviken. My supervisor and I also occasionally practiced taking our work outdoors, for instance by having walk-and-talk meetings in the forest.

What happens next, for you and your research?

– I’m still exploring my options for the next step. Right now, I’m trying to keep an open mind and take time to reflect on how to continue my career, either inside or outside of academia.

Read the dissertation

Read more about Yannick Klein