Effects of Inhalation of Emissions from Cedar Timber on Psychological and Physiological Factors in an Indoor Environment

Components extracted from cedar timber have been reported to have stress-reducing effects in humans. If the positive effects of cedar timber in indoor environments are scientifically proven, an indoor environment that utilizes cedar timber may contribute to the improvement or promotion of well-being in humans. In this study, we evaluated the effects of inhaling emissions of volatile constituents from cedar timber (Cryptomeria japonica) on the psychological and physiological factors in indoor environments. A case-control study with a crossover design was conducted with 10 subjects occupying two rooms that were controlled for interior materials, indoor climate, and room size. Cedrol and β-eudesmol were specifically detected in the case room. However, no significant differences were observed in psychological and physiological factors. There was a significant loss in vigor in the control group from the time before entering the room to the time after leaving the room; however, this loss in vigor was not seen in the case group. Temperature conditions were higher than the indoor environmental standard in Japan but similar in the two groups. Our results showed a minor positive change in vigor among participants exposed to cedar timber for a short term. Inhalation of emissions of volatile constituents from cedar timber may have positive effects in humans; however, further research on their efficacy is needed.