3 Physical And Mental Health Benefits of Walking In Nature

The Health Benefits Of Nature Therapy And Forest Bathing

Walking in nature has been found to improve both the subjective and objective measures of many health metrics, including lowered blood pressure, boosts to the immune system, decreased risk of heart failure, and a reduction of reported feelings of anxiety and depression.

These amazing benefits are due to the unique combination that a walk in nature provides. Walking exercise is known to help maintain good health, and this effect is magnified when combined with the power of the natural world. [1]

In the West, the terms Nature Therapy and Forest Bathing are both used, sometimes interchangeably, to describe a prolonged visit to a forested area. The concept itself has been popularised in recent years after glowing reports emerged from the Japanese therapy of ‘Shinrin-yoku’ (Shinrin means forest, yoku translates as bathe). Shinrin-yoku is a term created by the Japanese Ministry of Agriculture, Forestry, and Fisheries in 1982, and is characterised by ‘making contact with and taking in the atmosphere of the forest’. [2]

The term ‘Forest Bathing’ can alienate some people in the West. Indeed, the translation into English gives the activity a slightly ‘New Age’ feel that may sound abstract to the average person. However, Shinrin-yoku generally takes the simple form of walking in and/or spending time in forests, with the goal of achieving beneficial therapeutic outcomes. Variations include, laying down, sitting, or taking a long walk through nature.

For our purposes in this article, we will focus on the walking aspect of forest bathing. Walking through nature was simply the natural part of a human’s daily existence for most of history, and this activity perhaps only requires a marketable name in the modern world due to the increasing disconnection between humanity and nature.

Regardless of what you want to call it, research is clear that a nature walk can provide many health benefits to both body and mind, and here are three of the best! For a 60 second summary of this article, you can view our video here:

Scroll down and continue reading to learn three of the most vital health benefits provided by a walk in nature.

1. Walking In Nature Supports The Cardiovascular System

Walking outdoors is known to provide benefits to the cardiovascular system, with analysis showing that individuals who walk regularly have lower rates of cardiovascular disease than those who do not. When compared to inactivity, walking improves circulation throughout the body and increases the flow of oxygen to muscle tissues, including to the heart itself. The health benefits of a long walk are enhanced further when combined with a natural location such as a forest or woodland. A two hour walk in nature has been found to significantly reduce blood pressure, and the effect is more pronounced than those having the same length walk through an urban area. [3] [4] [5]

Sedentary lifestyles are associated with a higher risk of cardiovascular disease risk and cardiovascular mortality. Sitting time, such as in watching TV or regular long distance driving can increase the risk of premature cardiac mortality. [6] [7]

The evidence is clear that regular walking exercise can support the cardiovascular system, but evidence is also emerging that the act of being in nature can itself enhance this effect by stimulating the parasympathetic nervous system. Activation of the parasympathetic nervous system is associated with rest, relaxation, and recovery. The result is that simply being in nature can lower heart rates, and measurably reduce stress induced high blood pressure. [8]

Spending time in nature such as in a forest or woodland also helps to lower levels of pro-inflammatory cytokines involved in the development of hypertension, as well as many cardiovascular diseases. Among these markers of inflammation are a single chain glycoprotein called Interleukin 6 (IL-6). High levels of IL-6 are associated with an increased risk of myocardial infarction, stroke, and cardiovascular related mortality. [9]

Similarly, forest bathing is able to lower individual’s levels of the amino acid homocysteine. Whilst homocysteine is a normal part of the energy metabolism, excessive levels of homocysteine in the blood (hyperhomocysteinemia) can be caused by B-vitamin deficiencies, genetic defects, smoking, alcohol consumption, and other pathophysiological conditions. Raised homocysteine levels are associated with an increased risk of atherosclerosis and it’s related complications, including myocardial infarction, stroke, aortic aneurysm. However, research has found that a week stay in a broad-leaved evergreen forest can help to normalise an individual’s homocysteine levels. [10] [11]

2. Walking In Nature Reduces Depression And Anxiety

Walking through forests or woodlands has been found to decrease the negative moods of depression, dejection, tension, and anxiety. When compared to those walking through urban areas, individuals walking in nature report higher incidences of positive emotions including vigour and joy. A moderate intensity walk in itself provides benefits to cerebral blood flow, and the uplifting environment of a forest, park, or woodland can further help to elevate moods. Shinrin-yoku is a major form of relaxation in Japan, where it has been found to help to decrease the risk of psychosocial stress-related diseases. [12] [13] [14]

Regular light exercise in the form of walking can provide beneficial therapeutic outcomes for certain mental health issues including depression and anxiety. Regular walks have been revealed to assist in recovery from clinical depression. [15]

Interestingly, a 2018 meta-analysis found that that outdoor walking shows greater positive effects across a range of mental health outcomes when compared to walking indoors. This indicates that walking outside in the natural world provides a higher quality form of exercise than the same amount of steps taken on a treadmill or around the house. [16]

Noise pollution, air pollution, work pressure, and other stressors of urban life are increasingly driving humans to seek forms of stress relief. A study in Scotland found that individuals living in urban environments had a higher intake of psychotropic medication for anxiety, depression and psychosis when compared to residents of rural areas. [17]

This emotional difference between rural and urban settings is supported by a Japanese study analysing the effects of walks in 14 forests and 14 urban areas across Japan. Participants were given a questionnaire, which was completed prior to their walks in the forests and urban areas. Walks in forested areas resulted in much higher reports of positive emotions compared to participants who walked in urban areas. [18]

Even the sounds of nature can promote positive outcomes in mood and state of mind. Birdsong has been found to decrease feelings of anxiety, paranoia, and depression significantly more than urban soundscapes such as traffic noise. Indeed, not only did the urban sounds offer no support to the mental state, but exposure to traffic noise may actually increase feelings of sadness and symptoms of depression. [19]

The healing effect of nature however, is not only found in subjective reporting such as questionnaires, as even biological analysis provides strong evidence that nature reduces physiological stress. Analysis of urine samples taken after individuals have had a walk through a forested area or area of natural beauty has revealed lower volumes of the stress hormones adrenaline and noradrenaline.

Similarly the hormone cortisol is associated with chronic stress, and high levels of the hormone in the body over long periods can lead to anxiety, mood swings, acne, and reduced immune functioning. Salivary analysis of individuals who have just completed a walk in nature reveal decreased levels of cortisol in the participant’s saliva, indicating that the environment had actively reduced the individual’s stress levels. [20] [21] [22]

Whilst many of the mental health benefits of walking in nature are best when they are a regular part of a person’s life, even a single day trip to a forest can reduce stress and decrease feelings of anxiety and depression. A study testing participants after a single 4 hour 35 minute visit to a forest found immediate and significant elevation of moods. [23]

3. Walking In Nature Boosts The Immune System

It may sound like something from a fantasy novel, but research is beginning to find repeatable and reliable evidence that trees may supercharge our immune systems. All we have to do to unlock this superpower is simply take a walk in the presence of trees and shrubs.

Many trees, including oaks, pines, cedars, spruces, and various conifer species release antimicrobial and insecticidal compounds called phytoncides. Phytoncides are released into the air by trees to protect them against airborne pathogens and insects – a fact that is reflected in the name (phyton = plant, cide = kill). The exact combination of phytoncides released varies between tree species, and some have been better studied than others. For example, it is known that pine trees release alpha-pinene, carene, myrcene, limonene, and other terpenes as phytoncides. [24]

Phytoncides are a crucial part of a trees own immune system, protecting them against diseases and insects. Curiously when humans are exposed to these phytoncides and breathe them in, they have the curious effect of stimulating the human immune system too. After exposure to phytoncides, higher activity of Natural Killer (NK) cells in the body are observed. Whilst the volume of these cells remains the same before and after phytoncide exposure, the phytoncides seem to supercharge the immune cells already in the body. [25]

As their name suggests, Natural Killer cells are notable for their cytotoxic capabilities, meaning they are able to attack and kill harmful intruders in the body such as pathogenic bacteria and viruses. Whereas T-Cells require an antigen to activate them before they can combat an intruder, NK cells are able to attack and destroy harmful cells without initial priming. This distinguishing feature is why they are called ‘Natural’ Killer cells.

NK cells also play a large role in anti-cancer immunity, due in part to the secretion of cytokines and chemokines. The secretion of these compounds activates macrophages and dendritic cells to create a more complete immune response. NK cells have emerged as a promising therapeutic target in several solid tumours and haematological malignancies. [26]

Whilst simply being around trees can help boost the immune system, it is also worth noting that when combined with a walk, this effect is even greater. Aerobic exercise helps support the immune system, and improves a wide range of immunological biomarkers including boosts to leukocytes, lymphocytes, neutrophils, monocytes, and eosinophils. In practice, this means that those who walk regularly in nature will have an immune system that is better prepared to combat pathogens. For this reason, regular walking has been recommended as a protective measure against viral respiratory infections. For best results, it is recommended that the walk is over 15 minutes in duration, and of moderate intensity. [27]

How Often Should You Forest Bathe?

When considering how frequently one should go for a walk in nature, research has found that at least 150 minutes of walking exercise each week has been found to decrease the risk of heart failure and depression. Individuals who have a brisk walk in nature every day may see health benefits begin to manifest in as soon as 4 weeks. [28] [29] [30]

However, if your living situation or schedule doesn’t allow for daily nature walks, then a long walk once a week (such as on the weekends) may still offer long term health benefits. Indeed, many of the beneficial aspects of being in nature and forest bathing, such as lowered levels of stress hormones, can last more than a week. [25]

When it comes to the immune system boosting benefits of tree phytoncides, it is difficult to put an exact number on the prominence of the effect due to the variables involved. Different tree species release different blends of phytoncides, and thus the atmosphere of every forest will have it’s own unique blend of phytoncide compounds. The volumes of phytoncides also released vary by factors such as weather and the time of year. For example, phytoncide activity of pine trees is twenty times higher in the Summer than in the Autumn.

If your walk in nature happens to give you good exposure to tree phytoncides, the immune system boost can amazingly last for more than 30 days after the trip, as increased NK cell activity can be observed in analysis taken four weeks after a forest bathing trip. With this in mind, a forest bathe once a month would enable individuals to maintain a higher level of NK activity compared to baseline. However, to ensure one is getting a significant immune system boost, it is recommend to take a walk amongst trees and nature at least once a week. [31]

Conclusion

Walking in nature provides health benefits because it is a blend of so many beneficial aspects. The improved air quality, the sounds of the breeze and birds, and even the act of walking itself all help to make this activity an essential part of the healthcare routine. Forest environments can be viewed as therapeutic landscapes, in which the benefits of physical exercise are improved and enhanced.

It is always important to remember that human activity can disrupt natural ecosystems. If you are tempted to get outside and heal in nature, please remember to take litter home with you, and avoid the use of potential fire hazards such as cigarettes, camp fires, or portable BBQs.

Respect nature, and it can reward you with a healthier heart, better state of mind, and a supercharged immune system!