Definition: "An ergogenic aid is any substance or phenomenon that enhances performance "
How trees enhance your immune system
The concentrations used by the Japanese could theoretically occur in the body of people who breathe in these essential oils and substances. The Japanese already these substances phytoncides. Trees manufacture them to protect themselves against diseases and pests, but they also stimulate our immune system, the Japanese think.
Below you see how essential oils, alpha-pinene and 1,8-cineole made the Natural Killer Cells more effective, you can see below. Because of the exposure to these substances, the Natural Killer Cells made more perforin, granulysin and granzyme-A.
These substances enable Natural Killer Cells to attack cancer cells and cells infected with viruses. Perforin, granulysin and granzyme-A are agressive enzymes that can literally dissolve the cell membranes of faulty cells.
"Although the underlying mechanism of phytoncide-induced increases in intracellular perforin, granzyme A, and granulysin requires further study, the present findings strongly suggest that forest bathing may have beneficial effects on human immune function."
"We are planning to investigate this effect in a field study."
That field research has already been completed. Links to post about it below.