Have you ever noticed the physical and mental benefits of spending time in nature? How rejuvenating it is to hear the birds singing and the movement of the leaves, to smell all the different scents from trees, flowers and soil…I have no doubt you have!
I have grown up in a relatively unspoiled environment, in the countryside, surrounded by oak trees and mountain views. And…I never really realised how deeply this affected my wellbeing. After many years of living in cities, I suddenly did! And it dawned on me, all of a sudden, how badly I missed that experience.
During the past months of lockdown, I spent even more time than usual in the middle of the city, with no contact with nature at all, except for my beautiful indoor plants. My flat does not even have a balcony!
And so for the summer, I made a list of commitments for my wellbeing.
The first one relates to “forest bathing”.
Have you ever heard about it? This concept, coming from the East, has become increasingly popular in the West too in the past years.
It originated in Japan, where it is called “Shinrin-Yoku” and it is a traditional practice of immersing oneself in a forest environment, engaging all the 5 senses. In the 80s, it emerged as a preventive health care practice and healing technique [1, 2].
Does this mean that there is also scientific evidence for the health benefits of this practice?
Absolutely!
And it is exciting to see that in the last years there has been an exponential increase in the number of studies published on this very topic! Most of the research so far has been conducted in the East, in countries such as Japan, China and South Korea and research from European and other Western countries is emerging too.
And the findings of the research are even more exciting! What we intuitively know, that we are happier, healthier and perform better when we are immersed in nature, is confirmed by science.
Here some of the benefits that have been found.
Cardiovascular health
The practice of forest bathing has been consistently found to have significant beneficial effects on our cardiovascular health.
Blood pressure has been found to decrease significantly in study subjects with high or normal-high blood pressure when they are exposed to a forest environment [1,3]. The results are independent of the physical activity they carry out in the forest: whether or not the subjects were asked to walk, no significant differences in blood pressure were observed. It was also suggested that the blood pressure lowering effect is more significant for people who have a higher blood pressure to start with, than for people with normal blood pressure [3].
How big of a reduction are we talking about? The results vary among different studies and experiments performed. In a meta-analysis of 20 studies, the average reduction of systolic blood pressure was 3.15 mmHg. When looking only at the group with higher systolic blood pressure (>130 mmHg) though, the mean reduction was of 6.33 mmHg (going as high as 11.50 mmHg in one of the analysed studies!) [3].
Sounds good, right? Sitting (or walking) in the forest and lowering your high blood pressure!
Heart and pulse rates have also been shown to be decreased in the forest environment while heart rate variability has been found to be significantly increased [2,3].
Heart rate variability (HRV) – the variation in the time interval between heartbeats – is a measure associated with the activation of the parasympathetic nervous system - rest and digest - and the sympathetic nervous system - fight or flight. One study, as reported in [2], showed an 80% increase in the HRV indicators of parasympathetic nervous system activation in people experiencing forest-viewing compared to people in an urban setting.
This also demonstrates the efficacy of immersing oneself in a forest environment in reducing stress! And the effect on HRV is evident within just minutes of forest immersion!
Worth to make time for a few minutes in a green environment?
Stress, sleep and psychological wellbeing
The efficacy of the practice of forest bathing on stress reduction is not only demonstrated through measurements of HRV but also of stress hormones. In several studies, a reduction of cortisol and epinephrine was seen, while in others, a significant reduction was also observed in norepinephrine and dopamine [1].
And sleep is of course impacted too. Walking in the forest for 2 hours in the afternoon was found to decrease the perceived level of anxiety and increase sleep time [2]!
Of course, as we can all feel, immersion in a forest environment does have effects on our psychological wellbeing and this is especially true for people with chronic stress problems, who report a reduction in the negative feelings of hostility, depression and anxiety when spending time in the forest [2], and in those with depressive tendencies [4].
Immune health
Forest bathing was found to increase the number and activity of Natural Killer cells (involved in fighting cancer and virus-infected cells), as well as anti-cancer proteins [5]. In one of the studies, in which 12 men went on a day trip in a forest and took two 2-hour walk, the increase in NK cell activity was found to last for more than 7 days after the trip [6]. In another, the increase was observed as long as 30 days after a 3 day trip to the forest [5].
Such an effect on Natural Killer cells might be explained by the reduction in stress hormones.
Thinking of heading to the forest next Sunday?
And more!
Even more benefits have been linked to the practice of forest bathing. Just to mention a few: lower blood glucose in patients with type II diabetes when practicing forest-walking [2], increase in antioxidants [1], increase in self-esteem and health-promoting behaviours [1], improved attention [4] and even decrease in triglycerides [1].
What are the mechanisms involved? Why does immersion in a forest environment have such extraordinary effects on our wellbeing?
There are for sure many factors at play, considering that the forest is such a complex ecosystem. Moreover, what we experience in the forest is a 5-senses experience and the different sensory stimuli surely have a synergistic effect.
One of the explanations given for the lowering of blood pressure is the relaxation deriving from the fragrance of the trees - due to terpene components, such as phytoncide, which also have antioxidant and antiseptic properties [1].
Some other factors at play are negative air ions – which increase parasympathetic activity and have a positive effect on depression and blood glucose, oxygen and forest microclimate [1].
Are you convinced about the benefits of such a simple “intervention”? Would you like to score some extra points on wellbeing?
While research shows benefits that are simply related to being exposed to a forest environment, amplified benefits are seen when exercising or meditating in the forest!
What if I don’t have access to a forest?
You can do your best and still gather some benefits:
spending time in a park – access to green-spaces was also correlated with a positive self-perception of stress and general health,
hugging a tree,
keeping (and touching) plants and flowers at home ,
even just watching videos of natural environments [2]!
Now I’d like to hear from you! Do you enjoy “forest bathing”? And do you make it part of your wellness routine? Or what do you do instead? Let me know in the comments below!
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References
[1] Wen, Ye et al. “Medical empirical research on forest bathing (Shinrin-yoku): a systematic review.” Environmental health and preventive medicine vol. 24,1 70.
[2] Hansen, Margaret M et al. “Shinrin-Yoku (Forest Bathing) and Nature Therapy: A State-of-the-Art Review.” International journal of environmental research and public health vol. 14,8 851.
[3] Ideno, Yuki et al. “Blood pressure-lowering effect of Shinrin-yoku (Forest bathing): a systematic review and meta-analysis.” BMC complementary and alternative medicinevol. 17,1 409.
[4] Furuyashiki, Akemi et al. “A comparative study of the physiological and psychological effects of forest bathing (Shinrin-yoku) on working age people with and without depressive tendencies.” Environmental health and preventive medicine vol. 24,1 46.
[5] Li, Qing. “Effect of forest bathing trips on human immune function.” Environmental health and preventive medicine vol. 15,1 (2010): 9-17. doi:10.1007/s12199-008-0068-3.
[6] Li, Qing et al. “A day trip to a forest park increases human natural killer activity and the expression of anti-cancer proteins in male subjects.” Journal of biological regulators and homeostatic agents vol. 24,2 (2010): 157-65.
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