In Japanese households, it is customary to walk barefoot on wood floors. This study sought to clarify the physiological effects produced via tactile application of sugi (Cryptomeria japonica) to the sole of the feet, using the brain and autonomic nervous activities as indicators. Twenty-seven female university students (mean age, 21.9 ± 1.9 years) participated in this study. Oxy-hemoglobin (oxy-Hb) concentrations in the prefrontal cortex were determined using near-infrared time-resolved

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... copy. High frequency (HF), denoted parasympathetic nervous activity, and low frequency (LF)/HF indicated sympathetic nervous activity; both were measured using heart rate variability. The wooden material was unpainted sugi wood with two different finishes uzukuri brushing or sanding. A similarly sized marble plate served as a control. The sole of the feet of each participant touched each material for 90 s. The results found that the uzukuri wood significantly decreased oxy-Hb concentration in the left prefrontal cortex compared with touching the marble. Furthermore, compared to before contact, the uzukuri wood showed significantly decreased oxy-Hb concentrations in the right prefrontal cortex, increased ln(HF), and decreased the ln(LF/HF) ratio. Moreover, the contact with sanded wood significantly decreased oxy-Hb concentrations in the right prefrontal cortex compared with before contact. Thus, it is concluded that tactile application of sugi to the sole of the feet induced physiological relaxation.