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Japanese immunologist Dr Qing Li spent two decades studying forest exposure and…

2026-08-03 · 15:27 UTC ·@pa_coyote94151 ·1 min read

Brief

Mr PitBull Stories (via @pa_coyote94151) reports Japanese immunologist Dr Qing Li spent two decades finding that trees emit phytoncides which can enter the bloodstream, lower stress hormones (cortisol, adrenaline) and provoke immune changes lasting days; a hotel-room tree-oil experiment showed similar effects, though nature isn’t presented as a cure.

Why it matters

Japanese immunologist Dr Qing Li spent two decades studying forest exposure and identified natural airborne compounds called phytoncides; breathing forest air can allow some phytoncides to enter the bloodstream and is associated with lower cortisol and adrenaline levels.

Key details

  • Li’s research found measurable immune changes that lasted days after forest visits, and an experiment releasing tree oils inside hotel rooms produced similar effects, implying the chemicals themselves may contribute.
  • The post cautions forest exposure is not a cure for disease and that benefits may also come from exercise, cleaner air, quiet surroundings, and reduced stimulation.
Source evidence

Walk in the woods, breathe deeply, touch grass.

Mr PitBull Stories (@MrPitbull07)

A Japanese immunologist spent two decades studying what happens inside the human body when we spend time among trees.

The answer was more powerful than expected.

Trees release natural airborne compounds known as phytoncides.

When people breathe forest air, some of these chemicals can enter the bloodstream.

Research led by Dr Qing Li found that time in forests was associated with lower levels of stress hormones such as cortisol and adrenaline.

Some of these immune changes remained measurable for days after participants left the forest.

In one experiment, researchers even released tree oils inside hotel rooms and observed similar effects, suggesting that the chemicals themselves may play a role.

The compounds do not literally hunt stress hormones, and walking in nature is not a cure for disease.

Exercise, cleaner air, quiet surroundings and reduced stimulation may all contribute.

But the research suggests forests are doing more than helping us feel calm.

Every breath among the trees may be sending chemical signals throughout the body.

— https://nitter.net/MrPitbull07/status/2084229622082973837#m