Nature’s benefit after brain injury

I'm Claire McDonald and I work in independent practice and in the not-for-profit organization Neuro in Nature. I am incredibly passionate about neuropsychology and nature connection, and so it is heartwarming and a real privilege to be able to present today about Nature’s benefit after brain injury.

In terms of what I hope to be covering today, I'll talk a little bit about the history of nature and human health and well-being, and also introduce the practice of forest bathing for those who may not be aware of it. I will talk about how nature benefits physical, emotional, and cognitive well-being by talking about the research, but also some of the theories underpinning this and specific research with people with acquired brain injury. I'll then be going on to talk about some of the challenges that exist around nature connection for people with acquired brain injuries, but also some of the opportunities that neuro rehab professionals and individuals can connect with to support a better relationship with nature. I will end on some top tips for nature connection as well.

In terms of humans and nature, I think it's fair to say that our relationship with nature has really evolved over time. Unfortunately, this has been in the direction of disconnection rather than more connection. In ancient times, many cultures relied heavily on nature for healing practices. We used plants and herbs to treat illnesses and injuries, and our survival really depended on nature. We would have turned to nature for our diet; we would have worked the land. So, we needed to really observe nature and respect it in order to survive.

With the rise of industrialization, we experienced many incredible advancements in medicine and healthcare. We adopted more pharmaceutical approaches to managing medicine and health, and what this meant, particularly in Western societies, was that there was less focus on the health and healing properties of nature. Alongside this, we experienced rapid urbanization, so more and more people living within large towns and cities, working inside indoors, being less physically active, and able to access food from other sources. This resulted in a real growing disconnection with nature. We may have been living longer, but there seemed to be a real decline over time in our health and well-being. This is exactly what was observed in Japan in the 1980s, which prompted the establishing of forest bathing.

In the 1980s in Japan, there was a real tech boom. More and more people were spending time indoors behind screens, leading more sedentary lifestyles. What the government and healthcare professionals observed was that there was a significant increase in physical and mental health problems, such as autoimmune conditions, cancers, depression, mental health problems, and increased suicide rates. This resulted in the Japanese government coining the term 'shinrin-yoku,' which translates as 'forest bathing,' and promoting this as the antidote to tech-based burnout—a way of trying to get people to reconnect with Japan's forests.

So, what is forest bathing? No nudity or undressing is involved. It basically means immersing yourself in the forest air. What this looks like is a very slow and gentle walk in nature, with the emphasis on slowing down and connecting with the environment through your senses. When people are on a forest bathing walk, a guide would offer suggestions and prompts to help people direct their attention to the environment: looking at what they can see, maybe all the colors; looking at what they can touch; sensations; smells; and really important, listening for sounds. In doing so, what the guides are trying to achieve is a shutting down of those opportunities to engage in rumination and getting caught up in unhelpful thought processes. The emphasis is really on being present in nature. It's a very mindful activity. It's not about doing or a physical activity or getting in the steps, and it's not an intellectual pursuit. It's not about acquiring knowledge of trees or of the environment. It's about being present and really connecting with our senses.

Since the 1980s, this has led to a real explosion of more focused and scientific research really looking at the physical, cognitive, and emotional benefits of time spent in nature, and the results really are quite breathtaking. These have been replicated all over the world, from ancient woodlands to urban parks, gardens, and indoor settings as well.

In terms of the impact of nature on our bodies, there is an abundance of high-quality research, systematic reviews, and meta-analysis looking at the physical health benefits. Some of the short-term positive changes that have been noted include reduced salivary cortisol (the stress hormone in our bodies), reduced heart rate, reduced blood pressure, cholesterol improvements, heart rate variability improvements, and improvements in sleep. Over the longer term, connection and access to nature has been associated with a reduction in chronic health conditions and illnesses, such as cardiovascular disease, obesity, some cancers, and diabetes.

A lot of that research more recently has focused on understanding the immune system benefits of time spent in nature, specifically the impact of 'phytoncides.' These are the natural oils that are released by certain kinds of trees—cedars, pines, conifers. This is part of the tree's immune system response, how it keeps itself well and protected from threats, but this has a really complimentary effect on human immune systems. What the research has found is that exposure to these natural oils reduces inflammation within our bodies and promotes the activity of cells called 'natural killer cells.' These cells play a really important role in helping us to fight infections and things like cancer cells and tumors as well. The results are so compelling and convincing that this has led to some countries like Japan coming up with the idea of an 'optimal nature dose' or time spent in nature per month. In Japan, they recommend around two to three hours a month, but research has also highlighted that some of the significant physiological effects are experienced after just 20 minutes of nature connection per day. In terms of the psychological benefits, the research also highlights that it's the quality of nature connection that is really important, over and above time spent. So, it's moments, not minutes, in nature that really count.

There is a huge body of research, a high number of systematic reviews exploring the psychological benefits of nature connection. These extend across age groups, across cultures, across socioeconomic status, and across a wide range of clinical populations. These papers highlight that nature connection results in a reduction of symptoms of anxiety, stress, depression, and reduces rumination processes. Rumination is a risk factor for the development of a whole range of mental health illnesses, such as psychosis and eating disorders, and connection with nature seems to slow down and reduce this process. As well as reducing unhelpful symptoms, the research also highlights that nature can increase helpful mechanisms and experiences. Research has found that nature connection supports helpful emotional regulation skills and the experience of positive emotions—feelings of calm, awe, and wonder—and self-reported feelings of well-being and quality of life.

What's really nice is that the benefits seem to extend beyond the individual to wider communities and relationships. Research has found improvements in feelings of social connectedness and pro-social behavior towards others, but also towards nature itself. This is really important given what we know about concerns around climate issues. Research from the University of Derby has emphasized that the more closely we're connected to nature, the happier we are, the more worthwhile life seems, and the more willing we seem to be to take steps to protect nature and our wildlife. It's not just about taking from nature; it's about that relationship with nature itself.

Moving on to the impact of nature and our thinking skills, there is a real growing body of evidence to highlight the positive impact of nature connection on certain cognitive skills, particularly our attention, working memory, cognitive flexibility, and executive control. That has been noted on people's performance on cognitive assessments after exposure to nature. It's not just about actually being outdoors in nature; studies such as that by Berto in 2005 highlighted that even viewing photos resulted in performance or better performance on tasks of sustained attention versus those who viewed images of urban or built-up environments. These findings complement anecdotal and qualitative findings where people describe feeling more clarity after spending time in nature, or that they feel that they're able to think differently about a situation, or even feel more creative.

The research has highlighted the importance of nature connection for children and the impact on their learning and well-being. A paper by Taylor et al. highlighted that children living in urban areas who had a nature view from their living room windows performed better on tasks of working memory, impulse inhibition, selective attention, and concentration compared to children who didn't have that kind of view of nature. Within the education system, there's a growing recognition of the positive impact of nature on a child's learning, and more schools are introducing forest therapy programs to support connection opportunities. Given the younger generation's increased time spent with screens, this feels more important than ever.

What's actually going on inside the brain during nature connection? Studies answer this question by comparing brain activity using fMRI after a walk in nature compared to an urban walk. This paper by Sudak et al. highlighted reduced activation of the amygdala after a 60-minute walk in nature. The amygdala is our brain's threat control center, and it seemed that activity had reduced after that time in nature, which was correlated with participants' self-reports of feeling restored. Similarly, the paper by Bratman et al. observed decreased blood flow to the prefrontal cortex—the area of the brain involved in complex thought processes, decision-making, and behaviors—and this correlated with a self-reported decrease of rumination. It's helpful that more and more research is coming out that helps us understand the powerful impact that nature has on our brains, our bodies, and our emotional well-being.

I want to think a little bit more about the evidence base for people with acquired brain injury, because given the high rates of cognitive difficulties and psychological distress in this population, it feels like the evidence points to this being a really helpful intervention. There is not a huge body of evidence just yet, but what is there is really promising and positive. A systematic review by Vibal in 2020 identified seven high-quality studies looking at the impact of nature-based rehab interventions, including horticultural therapy, forest bathing, and outdoor adventure therapies. What these papers highlighted was that nature-based rehab improved the impact of acquired brain injury, including benefits to sensory-motor functions and cognitive functions. There were reported improved motivation, proactivity, and engagement in rehabilitation, improved mood and emotion regulation, and a sense of positive identity formation.

One of these studies looked at the brain activity of participants in horticultural therapy. Projects based around growing seeds and planting and seeing these through to harvesting appeared to result in changed activity in certain brain areas that tend not to be activated through traditional stroke rehab, such as visual and color processing areas, association areas, and sensory-motor areas. Then, Corson et al. worked with people who had a diagnosis of post-concussion syndrome and offered an 8-week nature-based intervention incorporating creative activities, outdoor-based mindfulness, and forest therapy. People reported a reduction in mental fatigue and increased quality of life. Even though they found some of the tasks challenging in terms of sometimes feeling overwhelmed with the sensory information, they experienced the tasks as really motivating and meaningful.

Why are these benefits occurring? Two key theories help us understand this. The first is 'Stress Reduction Theory,' proposed by Ulrich in the early 80s. This theory suggests that connecting with nature directly influences our nervous system, resulting in decreased sympathetic nervous system activity (our fight/flight response) and increased parasympathetic nervous system activity (our rest and digest system), which enables us to recover and heal. Ulrich completed research in the 1980s that shifted how people design hospitals and healthcare environments. He compared bile surgery patients who had a view of a tree out of a window with those who had a view of a wall. Those who had the nature view had shorter hospital stays, fewer complications, and required fewer doses of pain medication.

The second key theory looks at understanding the cognitive benefits: 'Attention Restoration Theory,' proposed by Kaplan and Kaplan in the late 80s. They suggest that busy urban environments are so highly stimulating that they require much more of our directed and voluntary attention capacities. This voluntary attention is a finite resource; over time, it becomes fatigued, and we struggle to sustain concentration. In contrast to urban environments, natural environments draw on 'involuntary attention.' They are softly fascinating and less demanding of our cognitive resources. Time spent in nature allows us to replenish and restore our voluntary attention capacities and results in improved cognitive functioning. They also highlighted that by virtue of us feeling less stressed in nature, this gives more cognitive space and capacity to focus on the things that we want to do.

I am also really passionate about hearing people's lived experiences. I want to share the experience of someone I've worked with for over a year who experienced a traumatic brain injury: James. He said: 'Since my accident, I really struggle walking and have poor short-term memory. It really frustrates me and leaves me confused. This is probably why nature and reserves are so important to me. You can put as little or as much time into it as you want, as long as you enjoy your time doing it. Even with a little food, be it nuts or seeds, you'd be surprised how much will come to you. By being outside in nature, I can relax; I don't feel rushed. This calms me down and frees up my mind to only think about or focus on what I want.'

Access to green space across the UK is not equal. Some barriers to nature connection include living in urban areas, lower socioeconomic status, ethnic minority groups, physical or sensory disability, and gender. Females and those from the LGBT community tend to feel less safe accessing local green spaces, with fear around risks. We need to advance the equality of nature connection opportunities.

How can we support people to access nature in adapted ways? There is an incredible body of research that highlights the positive impact of indoor nature connection. A paper by Okay et al. highlighted that viewing a bonsai tree for just one minute resulted in positive effects in patients with spinal cord injury, elderly adults, and those with dementia. Similarly, studies have looked at the impact of virtual forest bathing, using online images of nature, which was found to improve mood and decrease rumination in long COVID, spinal cord injuries, and MS. One of my favorite papers is by Li et al., who managed to convince a group of Japanese businessmen to spend 24 hours in a windowless hotel room, pumping in Woodland essential oils. Spending time absorbing those oils significantly enhanced natural killer cell activity, and the benefits persisted up to a month.

What can neuro-rehab professionals do? Identify and think about what opportunities are available throughout someone's rehab journey, from hospital gardens to looking at photos. Be curious: what was their pre-injury relationship with nature? Offer information and education about the health benefits. Problem-solve around accessibility barriers. Link in and work collaboratively with third-sector organizations. But also, think about your own connection with nature and your own well-being.

Some small tips for nature connection: Start small. It doesn't have to be a huge endeavor; just notice what's around you. Develop a routine, like having your morning coffee by the window. Connect with your senses: what can you see, hear, smell, touch, and taste? Invite nature inside: house plants, high-quality nature images, or online virtual forest bathing. Finally, create an emotional bond with nature: notice how you feel when connected. These are the feelings that are going to reinforce and help us to build on that connection.

Nature connection offers an abundance of opportunities for physical, mental, and cognitive well-being. These benefits go beyond the individual to pro-social and community benefits. We should be providing people with information about these benefits within their rehabilitation journey. It doesn't have to be time-consuming; we can weave these opportunities into daily life. Please give it a go.