趙 ヒョンジュ

Abstract In Japanese households, it is customary to walk barefoot on wooden floors. Previous reports on the psychological and physiological relaxing effects of feet contact with uncoated solid wood have already been published. However, there are no studies on the effects of feet contact with coated wood, which is commonly used for residential floors. This study aimed to validate the psychological and physiological relaxing effects of sole contact with oil-finished wood. In total, 27 women university students (mean age: 21.9 ± 1.9 years) participated in this study. Psychological indices such as the modified semantic differential method and the Profile of Mood States Second Edition were used. The oxyhemoglobin (oxy-Hb) concentrations in the prefrontal cortex were determined using near-infrared time-resolved spectroscopy. The sympathetic nervous activity and the parasympathetic nervous activity were measured using heart rate variability. The flat plate for tactile stimulation was oil-finished wood, and uncoated wood and marble were used for comparison. The sole of the feet of each participant touched each material for 90 s. Feet contact with oil-finished and uncoated wood had relaxing effects on psychological and physiological responses compared with marble. The relaxing effects of oil-finished wood and uncoated wood were similar. That is, they significantly increased subjective feelings of comfort and relaxation, improved mood states, and decreased oxy-Hb concentration in the left prefrontal cortex compared with marble. However, there were no statistically significant differences in terms of right prefrontal cortex and sympathetic nervous activities between oil-finished wood and marble. Oil-finished wood had a slightly weaker physiological relaxation effect than uncoated wood.

The purpose of this study was to evaluate the physiological effects of visual stimulation by a unique Japanese low wooden table on the prefrontal cortex and autonomic nervous activities. A within-participants experiment with 26 male university students was conducted in a Japanese-style room. The visual stimuli were a low wooden table (WT) made of Japanese cypress and a low cloth-covered table (control) for an exposure time of 90 s. Near-infrared spectroscopy was used to measure the prefrontal cortex activity in the left and right prefrontal cortices as an indicator of oxyhemoglobin (oxy-Hb) concentration. Autonomic nervous activity was measured as an indicator of sympathetic (low-frequency/high-frequency component ratio, LF/HF), and parasympathetic (high-frequency components, HF) nervous activities were assessed by heart rate variability. Furthermore, the modified semantic differential method and the Profile of Mood States 2nd edition were used to measure psychological responses. Physiologically, the oxy-Hb concentration in the left prefrontal cortex and ln (LF/HF) were significantly lower during visual exposure to the WT than to the control. Psychologically, more comfortable, relaxed, and natural impressions, as well as improved mood states, were reported during visual stimulation to the WT than to the control. This study demonstrated that viewing a WT led to physiological relaxation and had a positive psychological effect on the participants.

Growing interest in the relaxation effect of nature has elicited demands for scientific verification of the various natural elements. This study investigated the physiological and psychological responses of 27 females in their 20 s to viewing a waterfall and urban images (control) presented via a large, high-resolution display for 90 s. High-frequency [HF] for parasympathetic nervous activity and the ratio of low-frequency (LF)/[LF + HF] for sympathetic nervous activity by heart rate variability and heart rate were recorded. Simultaneous changes in oxyhemoglobin concentration in the prefrontal cortex were recorded by near-infrared time-resolved spectroscopy. The modified semantic differential method and Profile of Mood States Second Edition were used to assess the psychological effects on the participants after viewing each image. The results showed that viewing the waterfall image, compared with viewing the urban image, (1) increased sympathetic nervous activity; (2) provided comfortable, relaxed, and natural impressions; (3) improved mood states. In conclusion, visual contact with a waterfall image physiologically activated sympathetic nervous activity and psychologically evoked positive moods and feelings.