Psychological and Physiological Effects of Japanese Cedar Indoors after Calculation Task Performance

Abstract

In Japan, forest resources have not been used effectively, and much lumber from thinning has been left unused for a long time. These days, forest improvement has been reconsidered such that more wood will be used in public buildings and living spaces in Japan. Moreover, the arousing and/or sedative effects of wood extract fragrances have attracted increasing attention. We investigated the psychological and physiological effects of cedar's appearance and emissions in an indoor environment. Three test rooms varied in cedar cues: Room 1 contained cedar paneling, which provided both visual and odor cues; Room 2 had air circulating from the adjoining Room 1 (i.e., odor cues only); and the detached Control Room had no cedar-related cues. Twelve subjects (six males and six females) moved to the test room after they performed simple calculations for 15 minutes in an anteroom and stayed there for 10 minutes. Odor intensity in Room 1 was rated significantly higher than that of either Room 2 or the Control Room. Cedrol and β-eudesmol were specifically detected in Rooms 1 and 2 through an indoor air quality analysis. The subjects reported a faster rate of fatigue perception reduction in Room 1 via a visual analog scale (VAS). No between-subjects differences were detected in terms of physiological responses. The results indicate that an interior room that contains Japanese cedar facilitates psychological rehabilitation and supports well-being.