Objectives: The present study aimed to clarify the effects of viewing fresh roses on prefrontal cortex activity, autonomic nervous activity and subjective assessments of psychological relaxation.
Design: A crossover design, in which each experimental group crosses over from one treatment to another, was used.
Setting and interventions: A total of 15 female university students (mean age 21.7±1.1years) viewed fresh roses for 3min; the control consisted of no experimental stimulus.
Main outcome measures: Physiological effects on prefrontal cortex activity were determined by near-infrared time-resolved spectroscopy, which was assessed by measuring oxyhemoglobin (oxy-Hb) concentration in the left and right prefrontal cortex; effects on autonomic nervous activity were assessed by measuring heart rate variability (HRV) and heart rate. Modified semantic differential method and Profile of Mood States were used to determine subjective evaluations.
Results: Viewing roses induced: 1) a significant decrease in oxy-Hb concentrations in the right prefrontal cortex; 2) a marginally significant decrease in ln[LF/(LF+HF)] of HRV, which is associated with sympathetic nervous activity; 3) a significant increase in perceptions of feeling 'comfortable,' 'relaxed,' and 'natural;' and 4) a significant improvement in mood state.
Conclusions: These findings indicate that visual stimulation with roses induces physiological and psychological relaxation.
Keywords: Heart rate variability; Near-infrared spectroscopy; Physiological relaxation; Profile of mood states; Rose; Semantic differential method.
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