Spike Milligan famously quipped that a sure cure for seasickness is to sit under a tree. Turns out his goonish joke is rooted (heh heh) in physiological and psychological truth. ‘Forest bathing’ – simply being in the presence of trees – is a scientifically proven foil for all kinds of modern-day afflictions.
Forest bathing became part of a national public health programme in Japan in the 1980s, when the forestry ministry coined the phrase shinrin-yoku and promoted topiary as therapy.
Convinced that the programme was reaping benefits far beyond initial expectations, officials commissioned an eight-year-long study into the physiological and psychological benefits of simply being in the woods. Researchers measured the activity of human ‘natural killer’ (NK) cells in the immune system, which fight viruses and tumour formation, before and after subjects took to the trees.
They found that subjects showed significant increases in NK cell activity in the week after a forest visit, and these positive effects lasted a month following each weekend in the woods.
The reason, they concluded, is that trees emit various essential oils, collectively called phytoncide, to protect themselves from germs and insects. Forest air doesn’t just smell and feel fresher – inhaling phytoncide seems to actually improve human immune system function.
Another Japanese study showed that forests promote lower concentrations of cortisol, a lower pulse rate, lower blood pressure, greater parasympathetic (‘rest and digest’) nerve activity, and lower sympathetic (‘fight or flight’) nerve activity compared to city environments.
Trees soothe the spirit too. Study subjects showed significantly reduced hostility and depression scores, coupled with increased liveliness, after exposure to trees.
Doing nothing is key, the experts say. No hiking. No counting steps on a Fitbit. You can sit or meander, or take a gentle cycle ride to and from the trees, but the point is to relax rather than accomplish anything.
Oh, and leave your devices behind. That picture taken by your Facebook friend of a cloud shaped like a hippo’s bottom will be waiting for you when you return.