Research about the Japanese practice of forest bathing shows that time spent in nature lowers stress levels – and could even help fight cancer.
It’s widely assumed that escaping the noise and stress of the city to spend some time in nature is good for us. In recent years scientists have been putting this assumption to the test, and evidence is mounting of the positive effects of contact with nature on our physical, emotional and mental wellbeing.
Some of the most interesting evidence of the health benefits of nature is coming out of Japan, and revolves around the popular practice of ‘Shinrinyoku’ or ‘forest bathing’. The practice was introduced in 1982 in a prescient move by the Forest Agency of Japan to encourage a healthy lifestyle and decrease stress levels. Forest bathing has now become a recognised relaxation and stress management activity in Japan – but studies conducted in the last few years shows forest bathing is also increasing a component of the immune system that fights cancer.
Forest bathing experiments
Qing Li is a senior assistant professor at Nippon Medical School in Tokyo who is studying forest medicine. He is currently the president of the Japanese Society of Forest Medicine, which was established in 2007. Dr Li has conducted a number of experiments to test the effects of forest bathing on our moods, stress levels and immune system.
In one study the Profile of Mood States (POMS) test was used to show that forest bathing trips significantly increased the score of vigour in subjects, and decreased the scores for anxiety, depression and anger – leading to the recommendation that habitual forest bathing may help to decrease the risk of psychosocial stress-related diseases.
Other studies on immune function looked into whether forest bathing increases the activity of people’s natural killer (NK) cells, a component of the immune system that fights cancer. In two studies, small groups of men and women respectively were assessed before and after a two-night/three-day forest bathing trip. During the trips the subjects went on three forest walks and stayed in a hotel in the forest. Blood tests were taken before and after the trip, revealing a significant boost in NK activity in the subjects in both groups. The increase was observed as long as 30 days after the trip. Follow-up studies showed a significant increase in NK activity was also achieved after a day-trip to a forest, with the increase observed for seven days after the trip.
Dr Li attributes the increase in NK activity partly to breathing in air containing phytoncide (wood essential oils) like α-pinene and limonene, which are antimicrobial volatile organic compounds emitted from trees to protect them from rotting and insects.
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