Dr. Lawrence Cheng MD, CCFP(EM), MPHFunctional Medicine, Longevity, Mind/Body

There is no separation between us and nature.  We know this somehow on a deep intuitive sense whenever we are wandering in an old growth forest, swimming in the waves of the salty sea or just playing in the neighborhood park.  Human health is linked intricately in a multitude of ways and the understanding of these links are emerging.  Here, we delve into some the molecular mechanisms through which nature enhances physical, mental, and emotional well-being. 

1. Reduction of Stress and Anxiety 

Exposure to natural settings has been consistently linked to decreased levels of stress and anxiety. The concept of “biophilia” suggests that humans have an innate tendency to seek connections with nature and other forms of life. Natural environments stimulate the parasympathetic nervous system, responsible for relaxation and recovery. Activities such as walking in the park, hiking in the woods, or simply sitting by a lake can lower cortisol levels, the body’s primary stress hormone, promoting a state of calm and relaxation. 

On a molecular level, reduced cortisol levels can have widespread health benefits. High cortisol levels are linked to various adverse health outcomes, including hypertension, impaired cognitive performance, and immune suppression. The engagement of the parasympathetic nervous system in natural settings reduces the activation of the hypothalamic-pituitary-adrenal (HPA) axis, leading to a decrease in cortisol production. This hormonal modulation plays a critical role in alleviating stress and its related health issues. 

2. Improvement in Cognitive Function 

Nature also appears to have a rejuvenating effect on the brain. Studies have shown that time spent in natural settings can enhance cognitive functions such as memory, attention, and creativity. This phenomenon, often referred to as “attention restoration theory,” posits that natural environments provide a restorative experience that helps replenish cognitive resources depleted by the demands of modern life. The gentle, immersive quality of natural scenes allows the brain to recover from mental fatigue and improve overall cognitive performance. 

At the molecular level, exposure to nature has been linked to increased levels of brain-derived neurotrophic factor (BDNF), a protein that supports the survival, growth, and differentiation of neurons. BDNF is crucial for neuroplasticity—the brain’s ability to reorganize itself by forming new neural connections. Higher BDNF levels, particularly in the hippocampus, enhance memory, learning, and overall cognitive function. This molecular mechanism underlies the mental rejuvenation experienced after time spent in nature. 

3. Enhanced Physical Health 

Engaging with nature encourages physical activity, which is crucial for maintaining overall health. Outdoor activities such as walking, running, cycling, and gardening help improve cardiovascular health, muscle strength, and flexibility. Additionally, exposure to sunlight in natural settings is a vital source of Vitamin D, essential for bone health, immune function, and mood regulation. Regular physical activity in nature can reduce the risk of chronic diseases such as obesity, diabetes, and heart disease. 

The benefits of physical activity in natural settings are manifold. For instance, studies have shown that people are more likely to stick to an exercise routine when it involves outdoor activities, as opposed to gym-based workouts. The dynamic and varied terrain of natural environments also provides a more comprehensive workout, engaging different muscle groups and promoting better balance and coordination. Furthermore, the psychological benefits of exercising in nature—such as improved mood and reduced anxiety—serve to reinforce the habit, making it more sustainable in the long term. 

4. Boosted Immune Function 

Contact with nature can bolster the immune system. Phytoncides, antimicrobial compounds released by trees and plants, have been shown to enhance human immune function. Forest bathing practices has been associated with increased activity of natural killer (NK) cells, which play a crucial role in the body’s defense against infections and cancer. 

Phytoncides increase the production of anti-cancer proteins and improve the activity of white blood cells. Additionally, spending time in nature has been linked to lower levels of inflammation markers such as C-reactive protein (CRP) and interleukin-6 (IL-6), which are associated with chronic diseases. The reduction in stress hormones like cortisol also contributes to a stronger immune response, as chronic stress is known to suppress immune function. 

5. Emotional Well-being and Social Connectivity 

Natural settings provide a conducive environment for social interactions and community building, both of which are vital for emotional well-being. Parks, gardens, and nature reserves offer spaces for people to gather, fostering social connections and reducing feelings of loneliness and isolation. Furthermore, the aesthetic beauty of nature can evoke positive emotions such as joy, awe, and serenity, contributing to improved mood and overall happiness. 

Social interactions in natural settings are often more relaxed and positive compared to urban environments. The shared experience of enjoying nature can strengthen bonds and build a sense of community. Moreover, nature’s ability to evoke positive emotions can enhance these social interactions.  

6. Enhanced Sleep Quality 

Exposure to natural light and environments can also improve sleep patterns. Natural light helps regulate the body’s circadian rhythms, which are crucial for maintaining a healthy sleep-wake cycle. Spending time outdoors, especially in the morning light, can help reset the biological clock, leading to better sleep quality and duration. 

The impact of natural light on sleep is profound. The blue light from the sun in the morning helps regulate melatonin production, a hormone that controls sleep. By spending time outdoors, individuals can enhance their natural circadian rhythms, leading to earlier and more restful sleep. Additionally, the physical activity associated with spending time in nature further promotes healthy sleep patterns, as exercise is known to improve sleep quality. 


The relationship between nature and human health is complex and multifaceted. By reducing stress, enhancing cognitive function, promoting physical activity, boosting immune function, fostering social connections, and improving sleep, nature serves as a vital component of a holistic approach to health and well-being. As urbanization continues to rise, incorporating green spaces and natural elements into our daily lives becomes increasingly important, ensuring that the healing power of nature remains accessible to all. 

Incorporating more nature into our lives doesn’t require drastic changes. Simple activities like a daily walk in the park, gardening, or even placing a few plants in your home or office can make a significant difference. Communities and urban planners can also play a crucial role by designing cities with ample green spaces, parks, and accessible natural areas. 

Ultimately, the healing power of nature is a testament to our intrinsic connection with the natural world. By embracing this connection, we can enhance our well-being, improve our health, and find greater balance in our increasingly hectic and increasingly digital lives. So, take a moment to step outside, breathe in the fresh air, feel the sun, be more present and let nature work its medicine on your mind, body, and soul. 

“Nature itself is the best Physician.” 



Share this Post