The practice of forest bathing, rooted in mindfulness and meditation, involves immersing oneself in nature, often by walking through woodlands. Numerous studies highlight the health benefits of this experience, which can calm the mind and rejuvenate the body. This raises an intriguing question: could nature immersion become a formal therapeutic tool, prescribed by medical professionals to treat various health conditions?
Kathy Willis, a biodiversity professor at the University of Oxford, delves into this idea in her book Good Nature. Drawing on extensive evidence, she discusses not only the health benefits of nature but also presents quantitative data suggesting that doctors could incorporate nature into their treatment plans. Through her exploration of the sensory interactions between humans and the natural world, Willis uncovers the calming effects of touching wood, the enduring benefits of walking in pine forests, and the reasons why urban noise is particularly grating.
In a recent interview with Live Science, Willis shared her motivation for studying the health impacts of nature, the physiological responses triggered by natural landscapes, and how incorporating plants into our homes can enhance well-being.
The Spark Behind the Research
Reflecting on her journey, Willis said her interest was sparked during a large intergovernmental project on ecosystem services. “I kept coming across this paper that really piqued my interest,” she recalled. It revealed that gallbladder surgery patients who could view trees from their hospital windows required fewer pain medications and recovered faster than those whose windows faced brick walls.
“The fascinating part was that it wasn’t about air quality or pollution,” she explained. “There was a direct relationship between what patients saw and their recovery rates. Something within their sense of sight was accelerating healing.” This observation led Willis to question the mechanisms behind such phenomena, marking the beginning of her research journey.
More Than Just a Feeling
The physical and mental effects of nature extend beyond simple enjoyment. Willis explored how various senses—sight, smell, hearing, and touch—interact with nature to produce tangible physiological changes. “It’s an automatic response,” she said. For instance, nature can lower adrenaline levels, improve heart rate variability, and even stabilize hormonal imbalances.
To persuade medical professionals of nature’s potential, Willis emphasized the need for measurable evidence. “You can’t just say you feel generally better,” she said. “You need quantitative data showing exactly what’s happening in the body.”
Green Spaces and Human Physiology
One striking revelation is how the color green impacts the body. “When you look at green, particularly green and white leaves, three pathways are activated,” Willis explained. The autonomic nervous system is affected, lowering heart rate and blood pressure. The endocrine system responds with changes such as reduced stress-indicating salivary amylase levels. Lastly, psychological markers reveal decreased anxiety and increased calmness.
This phenomenon may be evolutionary. Willis pointed to studies showing that people prefer mid-complexity fractal patterns, such as open landscapes dotted with trees, over angular urban horizons. “When shown images of different landscapes, people consistently choose open savanna-like vistas,” she said. Interestingly, even children from tropical rainforest regions who had never left their environment favored savanna landscapes in such studies.
Smells That Heal
The chapter on smell surprised Willis the most. She discovered that inhaling plant-derived volatile organic compounds (VOCs) has significant physiological effects. “When you breathe in a plant scent, those molecules cross your lung membranes and enter your bloodstream,” she explained.
Walking in a pine forest, for instance, increases blood levels of pinene, a compound that interacts with biochemical pathways similarly to certain prescription drugs. “There’s compelling evidence that breathing in VOCs from trees like cedar reduces adrenaline and elevates natural killer cells, which help fight cancers and viruses,” Willis noted.
A groundbreaking study published in Oncotarget highlighted this effect. People living near Cupressaceae forests were found to be healthier, with lower instances of autoimmune diseases. Additionally, participants who walked in such forests for five hours experienced elevated natural killer cells, an effect that persisted for seven days.
Artificial Plants: No Substitute for the Real Thing
Studies comparing artificial and real plants reveal that the benefits of nature cannot be replicated synthetically. Japanese schoolchildren exposed to real pansies for 10 minutes experienced lowered blood pressure and feelings of calm. However, polyester-based artificial plants provided no such benefits. “It’s not just about sight,” Willis clarified. “The subconscious impact of smell plays a huge role.”
Gut Health and Biodiversity
The influence of nature extends to the gut microbiome. Biodiverse environments can positively alter the gut and skin microbiomes, leading to reduced inflammatory markers in the blood. Willis cited a Finnish study involving nursery children who played in three types of playgrounds: concrete, artificial matting, and Boreal forest soil.
“After 28 days, children exposed to forest soil had a completely new gut microbiome and significantly reduced inflammatory markers,” she said. Similar benefits were observed in adults working in offices with green walls, showing that biodiversity in one’s environment directly affects bodily systems.
Bringing Nature Indoors
For those unable to venture outdoors, Willis offered practical advice on incorporating nature into daily life. Victorian-era homes, often filled with plants, serve as an inspiration. “Having live plants in your sitting room or study can make a difference,” she said. Even something as simple as placing a vase of roses on a desk has measurable effects.
“Studies show that even non-scented roses—white or yellow—can lower blood pressure,” she added. “Why not have a vase of roses on your desk? It’s a small step we can all take without waiting for a prescription.”
Nature as Medicine
Willis’s research underscores the profound impact of natural environments on human health. From lowering stress hormones to boosting immune cells, the evidence suggests that nature’s healing powers are rooted in complex physiological processes. By acknowledging and harnessing these benefits, we could transform healthcare, integrating nature-based therapies into traditional medical practices.
Her findings remind us of the importance of reconnecting with the natural world. Whether through a walk in the forest, a vase of flowers, or a well-placed houseplant, the path to well-being might be closer than we think. As Willis puts it, “Wherever we are, we should all really be heading towards the bushy edges.”
