Breathe Deep, Feel Better: How Inhaling Plant Compounds Boosts Your Immune System and Calms Your Mind
Nature offers a simple, accessible way to enhance health through compounds we can inhale directly from the air. This phenomenon is often associated with the Japanese practice known as "Shinrinyoku," or forest bathing, which is described as a short, leisurely visit to a forest and is regarded as being similar to natural aromatherapy.
The key to these benefits lies in the volatile substances released by trees, primarily phytoncides (wood essential oils) and terpenes. These compounds, which include alpha-pinene and limonene, are antimicrobial volatile organic compounds (VOCs) that we breathe in during time spent in the forest.
Strengthening Immune Health
Inhaling forest air rich in these plant compounds has been shown to significantly benefit the human immune system.
Boosting Natural Killer (NK) Cell Activity
One of the most important findings regarding forest bathing is its ability to increase the number and activity of Natural Killer (NK) cells. NK cells are a type of white blood cell responsible for attacking virus-infected cells and tumors.
Studies have shown that forest bathing trips lead to a significant increase in NK activity and the number of NK cells. This effect is mediated by increased levels of anti-cancer proteins found inside the NK cells, such as perforin, granulysin, and granzymes.
The impact of breathing forest compounds is long-lasting: the increased NK activity in subjects who participated in a forest bathing trip was found to last for more than 30 days. This suggests that visiting a forest once a month could help maintain a higher level of NK activity. In contrast, visiting a city as a tourist did not produce these immunological benefits.
Calming the Mind and Reducing Stress
The inhalation of plant-based molecules can deliver beneficial effects to the brain, either directly through the olfactory system or through systemic circulation.
Reducing Anxiety and Stress
Breathing in these compounds can significantly reduce psychological distress. Forest bathing trips have been found to decrease scores for anxiety, depression, and anger and increase scores for vigor.
Research focused specifically on inhalable plant compounds, such as monoterpenes (MTs), shows they produce a specific anxiety-reducing effect. Exposure to high MT air concentrations during structured outdoor sessions decreased anxiety symptoms. The compound alpha-pinene appears to play a major role in this anxiety-reducing effect.
Furthermore, forest bathing significantly decreases the urinary concentration of stress hormones, including adrenaline and noradrenaline, suggesting that subjects were under lower stress during their time in the forest.
So, don't just stop and smell the roses, be sure to stop and smell the trees!