Autonomic responses during inhalation of natural fragrance of "Cedrol" in humans

Samantha Dayawansa, Katsumi Umeno, Hiromasa Takakura, Etsuro Hori, Eiichi Tabuchi, Yoshinao Nagashima, Hiroyuki Oosu, Yukihiro Yada, T. Suzuki, Tatketoshi Ono, Hisao Nishijo*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

81 Scopus citations


It is well known that odors affect behaviors and autonomic functions. Previous studies reported that some compounds in cedar wood essence induced behavioral changes including sedative effects. In the present study, we analyzed cardiovascular and respiratory functions while subjects were inhaling fumes of pure compound (Cedrol) which was extracted from cedar wood oil. Vaporized Cedrol (14.2±1.7 μg/l, 5 l/min) and blank air (5 l/min) were presented to healthy human subjects (n=26) via a face mask, while ECGs, heart rate (HR), systolic blood pressure (SBP), diastolic BP (DBP), and respiratory rates (RR) were monitored. Statistical analyses indicated that exposure to Cedrol significantly decreased HR, SBP, and DBP compared to blank air while it increased baroreceptor sensitivity. Furthermore, respiratory rate was reduced during exposure to Cedrol. These results, along with the previous studies reporting close relationship between respiratory and cardiovascular functions, suggest that these changes in respiratory functions were consistent with above cardiovascular alterations. Spectral analysis of HR variability indicated an increase in high frequency (HF) component (index of parasympathetic activity), and a decrease in ratio of low frequency to high frequency components (LF/HF) (index of sympathovagal balance) during Cedrol inhalation. Furthermore, Cedrol inhalation significantly decreased LF components of both SBP and DBP variability, which reflected vasomotor sympathetic activity. Taken together, these patterns of changes in the autonomic parameters indicated that Cedrol inhalation induced an increase in parasympathetic activity and a reduction in sympathetic activity, consistent with the idea of a relaxant effect of Cedrol.

Original languageEnglish
Pages (from-to)79-86
Number of pages8
JournalAutonomic Neuroscience: Basic and Clinical
Issue number1-2
StatePublished - 31 Oct 2003


  • Autonomic nervous system
  • Baroreceptor sensitivity
  • Blood pressure
  • Cedrol
  • Heart rate
  • Respiration

ASJC Scopus subject areas

  • Endocrine and Autonomic Systems
  • Clinical Neurology
  • Cellular and Molecular Neuroscience


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