How does the research work?

Last changed: 02 February 2023
Photo of people by a lake surrounded by forest

Nature-based health research is the overall concept which we use for all research into the link between nature, animals and human health. The research may examine garden rehabilitation, forest-, wilderness- or eco-therapy, or animals and nature in care and welfare. It may be about dogs in schools or the importance of nature to existential health. The studies cover a very wide range of academic disciplines, such as psychology, forestry, landscape architecture, medicine and physiotherapy. The methods vary, as do the research environments.

Research methods

Measuring physical reactions

One measure of a person relaxing and becoming calmer can be that their blood pressure and the concentration of stress hormones in the body fall. This is usually measured with a blood-pressure cuff or a saliva or blood test. Another measure used by researchers is heart-rate variability (HRV). This involves measuring the length of each heart beat, for example, using ECG - electrocardiography. The length of time between beats always varies. When a person relaxes, the measured value increases, when a person becomes stressed, it decreases. It is also possible to measure the oxytocin content of the blood, especially when investigating the significance of contact with animals. (Oxytocin is a neurotransmitter that is released from the brain into the blood from a pleasant tactile sensation. Amongst other things, increased oxytocin levels can lead to increased trust, reduced aggression and reduced stress.)

A common research method is to compare the values obtained before, during and after the nature stay, and/or to compare the values obtained during an activity (such as walking) with those obtained at rest. It is also standard to compare a person's data from an urban environment with the same measured values from a green space. These studies are usually performed on healthy adults.

Another way to measure – more rarely employed because it is relatively expensive and complicated – is to examine the activity of different parts of the brain before and after the nature stay using brain scanning and EEG (electroencephalography).

Self assessment, interviews and surveys

Many scientific studies that have a nature-based health perspective rely, at least in part, on participants analysing their mood themselves. They are then asked to fill in surveys or are interviewed in depth before and after an individual nature stay or entire rehabilitation periods. The researchers then have standardised protocols to help them, for example, Profile of mood states (POMS test), Becks Depression Inventory (BDI II) or Psychological general well-being (PGWB). When the surveys have fixed possible answers, statistics can be derived from the answers. In-depth interviews are sometimes used, where participants are asked to communicate their experiences.

Best with a defined control group

A study is evaluated more scientifically if, in addition to the group receiving the intervention, it also has a control group that does not receive it. The participants should be allocated to different groups. Optimal conditions are achieved if they do not know whether they are receiving treatment or whether they are in the control group, but these are almost impossible to achieve when it comes to research into nature-based interventions.

Research report with conclusions and publication

When all data is collected, it is considered as a whole and researchers evaluate and draw conclusions from it. The entire study is described in a research report which, after being assessed and approved by independent researchers, is published in a scientific journal. It is then searchable on the Internet in various databases, such as Google Scholar(which is open to everyone).

Research environments


Green spaces and parks

All outdoor research is complicated precisely because it takes place outdoors. There is a lot happening outdoors that the researcher cannot influence, but which may affect the outcome; the environment is never completely neutral or like a laboratory. The specific effect of the nature environment can therefore be difficult to determine. One parameter that can play a part is the weather. Outdoor temperatures, for example, if the weather is sunny, warm, snowy or rainy, impact the participants' experiences and how their bodies react. This is also true for sound levels. If you are close to a city, noise can disturb and irritate, even if you are in a large, park full of greenery.

These complications place great demands on the design of outdoor studies, which are therefore constantly being tweaked to be more accurate.

Much of the general research into nature and health takes place in the nature areas closest to universities and colleges. They are convenient for researchers, enabling them to find study participants relatively easily among the student population (which means that the study participants are approximately the same age, i.e. relatively young).

The garden, the outdoor classroom, the school playground

A garden, school playground or similar environment has the same starting point in terms of research as other outdoor environments, the advantage being that it can be recreated and adapted relatively easily. For example, different designs can be tested to identify what is most beneficial from the perspective of nature-based health. Protected corners can be created where you can be shielded from the surroundings, have special places for activities, leave a corner wild while the rest is pruned back, and so on. The outdoor rooms can be used for rehabilitation if people have exhaustion disorders, recreation for the elderly, play or educational activities for children and much more.

The garden as a healing and relaxing environment has been relatively well examined. For example, in the United States and the United Kingdom, cultivation and horticulture were used as a recovery method for traumatised soldiers as early as after the First World War. It became a component of psychiatric therapy. Horticultural therapy eventually became a university subject and was further developed to become a component of care of the elderly in the US, the UK, South Korea and several other countries.

In Sweden, garden research has focussed on people with exhaustion disorders, depression, anxiety, post-traumatic stress and similar therapy-resistant conditions where modern medicines do not seem to help. The garden has also been studied as a restful and stimulating environment for the elderly, as well as for stroke and Parkinson’s patients.

In Sweden, research has been conducted for many years at units such as Gröna Rehab [Green Rehab] in Gothenburg and the rehabilitation garden in Alnarp (now closed). A so-called multi-modal team, which can include, for example, an occupational therapist, physiotherapist, psychiatrist and horticulturist, has been working at both sites. It is not only the nature environment that is effective – other factors that also play a part include having experienced staff, a social community with people in the same situation, as well as activities such as mindfulness meditation, relaxation training, talking therapy, crafts etc.

Sea, lakes and water courses

As yet, water as a soothing and restorative environment has not often been the object of study. However, Finnish and British researchers have studied how people feel when they are close to water, and Swedish and North American research projects have ranked the beach as the number one place of relaxation in more general nature-based health research.

The forest and other wild nature

In Sweden and the other Nordic countries, the forest is a relatively unusual research environment, but researchers at SLU have carried out studies on participants who have been on extended sick leave with exhaustion disorders.

Eastern Asia, and Japan in particular, is further ahead in terms of research into the relaxing effects of the forest. Since the 1980s, many studies have been carried out in the context of an official public health project advancing the concept of forest bathing (usually walking slowly and calmly, taking in the forest with all the senses; in Japanese shinrin-yoku) and forest therapy (therapeutic activities with doctors or a specially trained forest therapist). Research lays the foundation for this by showing that the forest helps. Its mission, for any municipality willing to pay the fee, is also to certify therapeutic forests and walking paths around Japan, while a special organisation is training guides to guide the way for stressed urban residents and others.

In Finland, researchers have studied the effect of different types of forest on well-being. They have also studied and proposed what a forest should look like in order to function as a rehab forest. Swedish researchers have also done the same. In addition, they have calculated the cost to a landowner of earmarking most of the forest for recreation and rehabilitation as opposed to harvesting.

In countries such as the USA and Australia, Wilderness therapy or Outdoor adventure therapy has been available to young people and adults for many years. The researchers are looking at people are impacted by continuous periods of outdoor group activities. It may, for example, be about young people with drug problems or psychiatric disorders. Norwegian researchers have carried out similar studies. Swedish and North American research has also studied how being outdoors and living in a tent for a few days can impact and restore the internal body clock.

In the laboratory

In a laboratory or similar facility, researchers can create an environment that is exactly the same for everyone taking part in a study. They try to mimic the nature-based experience as best they can, for example, by allowing participants to experience images of nature and nature films wearing 3D glasses. It is also possible to listen to nature sounds through headphones. The researchers also sometimes add scents to further mimic the real environment.

The reactions of the participants are measured, for example by EEG (electroencephalography), which records electrical impulses in the brain, or using the more advanced fMRI method (functional magnetic resonance imaging). This type of study has been carried out in Sweden and in many other places around the world.

In Japan, the scent of coniferous forest has been released in hotel rooms to see if and how it affects the immune system of stressed urban residents. Pure laboratory experiments have also shown that scent molecules from the forest, so-called phytoncides, increase the number of NK cells in the immune system and increase their activity.

At the desk

Nature-based health research can also involve studying statistics from different databases and drawing conclusions from them.

Researchers sometimes follow whole populations or other large population groups for extended periods. They may do so to collect and evaluate statistics on lifestyle and mortality. It is then possible to compare, for example, population groups living in different environments, such as in the inner city or near to green spaces. Large population comparisons of this type have been made in, for example, England, the Netherlands and the United States.

These studies have the advantage of containing data that affects very many people, the disadvantage being that it is often difficult or impossible to identify the cause and effect of the outcomes.


In the therapy room or hospital room

Modern psychiatry was early to identify the positive effect a pet can have on a person's well-being. One of the research pioneers, Boris Levinson, had not had time to shut his pet dog, Jingles, into another room when his client, an autistic child, entered the therapy room. The dog and the child immediately interacted and Levinson let the dog stay. The dog became a bridge between the therapist and the child and the entire therapy situation changed for the better. In 1961, Levinson published scientific documentation about this and many other researchers and practitioners followed. Israel and the USA dominate the research area today. Another field of research is companion animals in hospitals. The animals come on temporary visits, for example, to paediatric units.

The stable and the farm

Equine-assisted interventions are employed in both physical and mental therapy and have increasingly become the subject of scientific research. People with different types of functional limitation, such as impaired mobility, autism, ADHD, schizophrenia, or with addiction problems, participate partly in work with the horses in the stable and partly in riding activities. This can range from day-to-day activities and therapy to care and rehabilitation. The research indicates that it is not only interaction with the horse but also the social environment and physical work in the stables that contributes to the positive experience.

In Sweden, the concept of Green Welfare is used for care, rehabilitation, social activation and housing on farms with animals, focussing in particular on receiving people with special needs. In the region of Skåne, the focus has been on what is known as nature-assisted rehabilitation (NAR) on farms for people on sick leave which currently involves eight specially selected units. The activities are based on research carried out at the Alnarp Rehabilitation Garden. In Norway there are similar projects – Inn på tunet [Green Care Norway] – throughout the country. Among other things, the project has conducted research into how dementia sufferers can benefit from farm stays.

Assisted housing, pre-school and other public facilities

According to research, social service dogs, cats, hens and other animals are sometimes found in homes for the elderly and dementia sufferers with good outcomes. Animals, such as dogs, are also used in pre-school and school activities, and in prisons and other institutions. Research studies in relation to this have also been carried out.

/Text: Åsa Ottosson