Effects of Fragrance Components of Abies holophylla Max. on Stress Relief and Improvement of Vascular Function

The purpose of this study was to investigate the effects of the fragrance of Abies holophylla Max., which is known to contain α-pinene, β-pinene, and limonene, etc., on stress relief, vascular function and autonomic nervous system. In this crossover design study, 15 healthy workers without otolaryngologic disease (37.6 ± 6.8 years old) were randomized to either (1) plant fragrance inhalation or (2) odorless air inhalation by an experiment coordinator. Compared with odorless air inhalation, plant fragrance inhalation decreased brachial SBP (117.64±4.89 to 108.36± 3.92 mmHg, p=.001), brachial DBP (75.00±3.21 to 71.71±2.30 mmHg, p=.004), central SBP (104.86±4.22 to 97.21±3.28 mmHg, p=.001), central DBP (75.00±3.14 to 71.93±2.43 mmHg, p=.015), and heart rate (66.57±1.84 to 63.00±1.72 bpm, p<.001). Arterial Stiffness Indexes such as AIx (13.00±3.75 to 5.71±4.19%, p=.000) and AIx@75 (7.71±3.51 to -0.29±3.93%, p=.001) were also decreased significantly when fragrance was inhaled. In addition, all of the interventions had significant interventions except brachial and central DBP. Heart rate variability (HRV) and flow-mediated dilation (FMD) were significantly improved in plant fragrance inhalation vs. odorless air inhalation (p=.006, p=.039). In conclusion, this study demonstrates that fragrance components of A. holophylla Max. have positive effects on the autonomic nervous system and improve vascular function. Therefore, it will be helpful for the selective use of plants to increase the treatment effect in horticultural therapy.