Forest Bathing: Do Forest Monoterpenes Affect Physiological Processes That Promote Health?
Abstract:
This paper considers the health effects of ‘Forest Bathing’ and whether such health effects are mediated by forest volatile organic compounds (VOCs) and/or they’re whether these are through ‘mindfulness’ practices that activate health-promoting physiological processes. The VOCs considered are the monoterpenes D-limonene, α-pinene, ∆3-carene and 1,8-cineole. Clearly, some of the health benefits of forest bathing come from ‘mindfulness’ practice that promote parasympathetic activities. There is also clear evidence that the 4 monoterpenes at high enough concentrations can activate physiological processes that lead to better health outcomes, particularly with decreases in anxiety and decreases in inflammation. These processes appear to involve activation of the adenosine A2A receptor and down-regulating activation of Nuclear Factor kappa B. The question is whether the monoterpenes can do so at the concentrations encountered in a forest setting. There is some research that indicates that forest atmospheric concentrations of monoterpenes can activate physiological processes that promote health but more research is required to definitively establish this. This review ends with suggestions on how to unequivocally answer the question whether the 4 monoterpenes considered at concentrations found in a forest, or their metabolites, can activate physiological processes that promote health, in particular physiological processes that decrease anxiety and inflammatory conditions and promote better endothelial function.
