Abstract
Aromatherapy with essential oils is one of the most popular complementary medical tools for improving sleep quality. However, only a few reports have objectively measured the effects of essential oils on sleep. Here, we used objective and subjective measures to analyze the effects of the essential oils of lavender (Lavandula angustifolia) and sweet orange (Citrus sinensis) on the sleep quality of healthy university students. The participants were monitored for 15 consecutive nights as they inhaled lavender oil and sweet orange oil, in a crossover design. Their sleep was monitored objectively by actigraphy, and total sleep time (TST), sleep efficiency, sleep latency, and wake after sleep onset (WASO) were analyzed. Their sleep was analyzed subjectively using Oguri–Shirakawa–Azumi (OSA) sleep inventory scores. Inhalation of an essential oil improved sleep measures only in participant whose sleep quality was poor in the control condition. Lavender seemed more effective than sweet orange in objective measures, especially in improving sleep latency. In the subjective sleep analysis, the essential oils improved sleep maintenance, dreaming, and sleep length in subjects who had poor sleep quality. Sweet orange seemed more effective than lavender in the subjective sleep measures. The difference between the two oils suggests that expectancy bias had little effect on the hypnotic effect of lavender on objective sleep. Although no obvious effect was observed in good sleepers, the inhalation of lavender oil could be effective for helping poor sleepers improve objective sleep quality.
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References
Doi Y. Prevalence and health impacts of sleep disorders in Japan (in Japanese). J Natl Inst Public Health. 2012;61:3–10.
Doi Y, Minowa M, Uchiyama M, Okawa M. Subjective sleep quality and sleep problems in the general Japanese adult population. Psychiatry Clin Neurosci. 2001;55:213–5.
Cappuccio FP, Cooper D, D’Elia L, Strazzullo P, Miller MA. Sleep duration predicts cardiovascular outcomes: a systematic review and meta-analysis of prospective studies. Eur Heart J. 2011;32:1484–92.
Beihl DA, Liese AD, Haffner SM. Sleep duration as a risk factor for incident type 2 diabetes in a multiethnic cohort. Ann Epidemiol. 2009;19:351–7.
Jansson-Fröjmark M, Lindblom K. A bidirectional relationship between anxiety and depression, and insomnia? A prospective study in the general population. J Psychosom Res. 2008;64:443–9.
Xie L, Kang H, Xu Q, Chen MJ, Liao Y, Thiyagarajan M, O’donnell J, Christensen D, Nicholson C, Iliff JJ, Takano T, Deane R, Nedergaard M. Sleep drives metabolite clearance from the adult brain. Science. 2013;342:373–7.
Tworoger SS, Lee S, Schernhammer ES, Grodstein F. The association of self-reported sleep duration, difficulty sleeping, and snoring with cognitive function in older women. Alzheimer Disease Assoc Disord. 2006; 20: 41 – 8.
Maddocks-Jennings W, Wilkinson JM. Aromatherapy practice in nursing: literature review. J Adv Nurs. 2004;48:93–103.
Cooke B, Ernst E. Aromatherapy: a systematic review. Br J Gen Pract. 2000;50:493.
Lillehei AS, Halcon LL. A systematic review of the effect of inhaled essential oils on sleep. J Altern Complement Med. 2014; 20: 441 – 51.
Fismer KL, Pilkington K. Lavender and sleep: a systematic review of the evidence. Eur J Integr Med. 2012;4:e436-e47.
Howard S, Hughes BM. Expectancies, not aroma, explain impact of lavender aromatherapy on psychophysiological indices of relaxation in young healthy women. Br J Health Psychol. 2008; 13: 603 – 17.
Raudenbush B, Koon J, Smith J, Zoladz P. Effects of odorant administration of objective and subjective measures of sleep quality, post-sleep mood and alertness, and cognitive performance. North Am J Psychol. 2003; 5: 181 – 92.
Goel N, Kim H, Lao RP. An olfactory stimulus modifies nighttime sleep in young men and women. Chronobiol Int. 2005;22:889–904.
Perl O, Arzi A, Sela L, Secundo L, Holtzman Y, Samnon P, Oksenberg A, Sobel N, Hairston IS. Odors enhance slow-wave activity in non-rapid eye movement sleep. J Neurophysiol. 2016; 115: 2294–302.
Sadeh A, Hauri PJ, Kripke DF, Lavie P. The role of actigraphy in the evaluation of sleep disorders. Sleep. 1995;18:288–302.
Jean-Louis G, Kripke DF, Cole RJ, Assmus JD, Langer RD. Sleep detection with an accelerometer actigraph: comparisons with polysomnography. Physiol Behav. 2001; 72:21–8.
Ancoli-Israel S, Cole R, Alessi C, Chambers M, Moorcroft W, Pollak CP. The role of actigraphy in the study of sleep and circadian rhythms. Sleep. 2003; 26: 342–92.
Littner M, Kushida CA, Anderson WM, Bailey D, Berry RB, Davila DG, Hirshkowitz M, Kapen S, Kramer M, loube D, Wise M, Johnson SF. Practice parameters for the role of actigraphy in the study of sleep and circadian rhythms: an update for 2002. Sleep. 2003; 26:337–41.
Sadeh A. The role and validity of actigraphy in sleep medicine: an update. Sleep Med Rev. 2011; 15: 259–67.
Goes TC, Antunes FD, Alves PB, Teixeira-Silva F. Effect of sweet orange aroma on experimental anxiety in humans. J Altern Complement Med. 2012;18:798–804.
Guzmán-Gutiérrez SL, Navarrete A. pharmacological exploration of the sedative mechanism of hesperidin identified as the active principle of citrus sinensis flowers. Planta Med. 2009;75:295–301.
Cole RJ, Kripke DF, Gruen W, Mullaney DJ, Gillin JC. Automatic sleep/wake identification from wrist activity. Sleep. 1992;15:461–9.
Yamamoto Y, Tanaka H, Takase M, Yamazaki K, Azumi K, Shirakawa S. Standardization of revised version of OSA sleep inventory for middle age and aged (in Japanese). Brain Sci Mental Disord. 1999;10:401–9.
Hirokawa K, Nishimoto T, Taniguchi T. Effects of lavender aroma on sleep quality in healthy Japanese students. Percept Mot Skills. 2012; 114: 111–22.
Yamagishi R, Yokomaku A, Omoto F, Misao K, Takada K, Yoshimatsu S, Abe A, Hayashi M. Sleep-improving effects of the aromatic compound heliotropin. Sleep Biol Rhythms. 2010; 8: 254–60.
Acebo C, Sadeh A, Seifer R, Tzischinsky O, Wolfson AR, Hafer A, Carskadon MA. Estimating sleep patterns with activity monitoring in children and adolescents: how many nights are necessary for reliable measures? Sleep. 1999;22:95–103.
Kanda Y. Investigation of the freely available easy-to-use software ‘EZR’ for medical statistics. Bone Marrow Transpl. 2013;48:452–8.
Ferguson C. An effect size primer: a guide for clinicians and researchers. Prof Psychol Res Pract. 2009;40:532–8.
Nagai K, Niijima A, Horii Y, Shen J, Tanida M. Olfactory stimulatory with grapefruit and lavender oils change autonomic nerve activity and physiological function. Auton Neurosci. 2014;185:29–35.
Shen J, Niijima A, Tanida M, Horii Y, Maeda K, Nagai K. Olfactory stimulation with scent of grapefruit oil affects autonomic nerves, lipolysis and appetite in rats. Neurosci Lett. 2005; 380: 289 – 94.
Tanida M, Niijima A, Shen J, Nakamura T, Nagai K. Olfactory stimulation with scent of essential oil of grapefruit affects autonomic neurotransmission and blood pressure. Brain Res. 2005;1058:44–55.
Shen J, Niijima A, Tanida M, Horii Y, Maeda K, Nagai K. Olfactory stimulation with scent of lavender oil affects autonomic nerves, lipolysis and appetite in rats. Neurosci Lett. 2005; 383: 188 – 93.
Tanida M, Niijima A, Shen J, Nakamura T, Nagai K. Olfactory stimulation with scent of lavender oil affects autonomic neurotransmission and blood pressure in rats. Neurosci Lett. 2006; 398: 155 – 60.
Acknowledgements
The authors thank the participants for taking part in this study. The authors also thank the assistance provided by H. Miyama, M. Kazato, and H. Maruyama.
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All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Research Ethics Committee (Josai International University) Permission Number: 32 (dated April 18, 2013).
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Informed consent was obtained from all individual participants included in this study.
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Kawai, H., Tanaka, S., Nakamura, C. et al. Effects of essential oil inhalation on objective and subjective sleep quality in healthy university students. Sleep Biol. Rhythms 16, 37–44 (2018). https://doi.org/10.1007/s41105-017-0121-y
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DOI: https://doi.org/10.1007/s41105-017-0121-y