Forest bathing

A Japanese government forestry programme from 1982, now the best-evidenced practice in this section — though the evidence is weaker than the marketing and stronger than the sceptics expect.

What it is

Shinrin-yoku, "forest bathing": spending unhurried time among trees with deliberate attention to the senses, without a destination, a distance target or a device.

It is not hiking, and the distinction is the practice. There is no summit, no pace and no tracking. The instruction is to go slowly enough to notice — light through leaves, the smell of leaf litter, the sound of the canopy — for somewhere between twenty minutes and a few hours.

Where it came from

Unusually for anything in this section, it has a documented founding date and no ancient lineage claimed.

The term was coined in 1982 by the Japanese Forestry Agency, under its then director-general Tomohide Akiyama, as a public health and forest-appreciation programme. Japan is heavily forested and had a population increasingly urban, sedentary and overworked; shinrin-yoku was policy, promoting both wellbeing and the value of the national forest estate.

The cultural ground was already there — Shinto's chinju no mori, the sacred groves surrounding shrines, and a long aesthetic tradition of attention to seasonal nature. But the practice as named is a modern public health initiative, and its advocates say so. That honesty is rarer here than it should be.

Research followed from the 1990s, principally by Yoshifumi Miyazaki at Chiba University and Qing Li at Nippon Medical School, and Japan designated official Forest Therapy Bases from 2006.

How it is done

Walk slowly, or sit. Leave the phone. Attend deliberately to each sense in turn. Some programmes use structured invitations; many do not. Guided sessions exist, and a certification industry has grown up around them, which is worth noting given that the practice consists of walking slowly in a wood.

What we can and cannot say

We can say there is a real research literature, which sets this apart from most of this section. Studies report reductions in salivary cortisol, lower blood pressure and pulse rate, shifts in heart rate variability toward parasympathetic dominance, and improved scores on mood inventories, in forest settings compared with urban ones. Qing Li's work additionally reports increases in natural killer cell activity persisting for some days after a forest trip, attributed to inhaled phytoncides — the volatile antimicrobial compounds trees emit.

We can say the evidence is weaker than the popular presentation. The limitations are real and mostly unavoidable: sample sizes are typically small, often young male students; blinding is impossible, since participants obviously know whether they are in a forest; the comparison condition is usually a city street, which differs in noise, air quality, traffic, crowding, surface underfoot and social threat as well as in trees; much of the work comes from a small number of groups in one country, with the publication and cultural biases that implies. The immune findings in particular have not been widely replicated independently, and the causal step from phytoncides to NK activity in a free-living human is not established.

We can say the broader claim is on much firmer ground. The epidemiology of green space — large cohort studies linking residential greenness to lower all-cause mortality, better mental health outcomes and lower cardiovascular risk — involves populations in the hundreds of thousands and is far more robust than the shinrin-yoku trials. Whether the mechanism is air quality, physical activity, noise reduction, social contact, attention restoration or something else is genuinely open.

We cannot say a forest does something a park cannot, or that guided sessions beat going alone, or that a certificate is required. What can be said, and it is enough, is that time spent unhurried among trees appears to be good for people, that nobody has found a downside, and that it costs nothing.

That makes this the rare page here where the honest verdict is simply: yes, probably, go and do it.

What it is

Where it came from

How it is done

What we can and cannot say

Further reading