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Effects of odorant administration on objective and subjective measures of sleep quality, post-sleep mood and alertness, and cognitive performance
... Over the past three decades, research on olfaction has dramatically escalated, with researchers connecting the workings of the olfactory system and the psychological interpretations of odors in terms of mood, behavior, and performance [9][10][11][12][13][14][15]. Existing research on the psychological and cognitive aspects of odors is compelling; odors have extensive effects on the human central nervous system [12,14,15]. ...
... Over the past three decades, research on olfaction has dramatically escalated, with researchers connecting the workings of the olfactory system and the psychological interpretations of odors in terms of mood, behavior, and performance [9][10][11][12][13][14][15]. Existing research on the psychological and cognitive aspects of odors is compelling; odors have extensive effects on the human central nervous system [12,14,15]. It is reasonable to consider that the human body may respond to odors presented during sleep [16][17][18][19][20]. ...
... Many studies have been performed to analyze sleep quality in the presence of different odors. For example, Polysomnographic measurements have been performed to examine the effects of peppermint [17,28,29], lavender [30,31], jasmine, and lavender [15] odors on sleep; sleep patterns; relaxation effects; alertness; cognitive performance; and mood. ...
In this study, the volatile compounds of white mother chrysanthemum flower were analyzed through gas chromatography-mass spectrometry (GC–MS) and gas chromatography–olfactometry (GC–O) analysis approaches. To investigate the effect of white mother chrysanthemum odor on sleep quality, polysomnography sleep tests and subjective evaluations were performed. A skin-lightening test was performed to investigate the effects of the newly developed night cosmetic cream. During the polysomnography sleep test, 20 female subjects were tested on two separate days: one with fragranced cream and the other with fragrance-free cream. The skin-lightening test was composed of two groups: 10 subjects applied fragrance-free night cream and other 10 subjects applied fragranced night cream. They applied the cosmetic cream to their faces once a day before sleep for 4 weeks. The results show that sleep efficiency was significantly affected by the mother chrysanthemum odor but found that the reconstituted fragrance of white mother chrysanthemum flowers had a skin-lightening effect through sound sleep.
... The reference lists of these identified studies and systematic reviews, along with OVID Medline electronic article mappings, yielded eight additional studies meeting the inclusion criteria. A total of 15 human studies on inhaled essential oils and their effect on sleep were found, 5,[36][37][38][39][40][41][42][43][44][45][46][47][48][49] and their methods and results were summarized and compared (Table 1). ...
... Eleven of the 15 studies were RCTs with single-or doubleblinding. [36][37][38][40][41][42][43][44][45][46]49 Blinding is a challenge in essential oil research because of the distinct odor of each essential oil. Blinding techniques included using language that was not specific, avoiding visual cues, embedding blocks of odor stimulus in the airflow, administration during sleep, and use of more than one essential oil or substance with an aroma. ...
... 5 Crossover design was used in four of the studies using controls or placebos. [42][43][44]49 Ten RCTs screened for olfactory abnormalities [36][37][38][40][41][42][43]45,46,49 and 11 screened and controlled for sleep abnormalities in the design. 36,37,40,42,43,45,46,49 In addition, most used more than one measurement tool and combined objective and subjective measurements. ...
Objectives:
Diabetic nephropathy (DN) is a serious and common complication of diabetes mellitus leading to end-stage renal disease in up to 30% of diabetic patients. The first manifestation of DN in humans is microalbuminuria, which arises from the increased passage of albumin through the glomerular filtration barrier. Reactive oxygen species, inflammatory cytokines, and growth factors are key players in the context of damage to the glomerular filtration barrier.
Interventions:
In this study the herbal combination Canephron(®) N, containing lovage root, rosemary leaves, and centaury herb, was administered to patients with DN to study the effects on microalbuminuria and overall oxidant/antioxidant status. An open study involving 59 patients with DN was performed to compare the effects of Canephron N administered concomitantly with standard antidiabetic therapy and an angiotensin-converting enzyme (ACE) inhibitor, with the standard therapy and ACE inhibitor treatment alone.
Results:
After 6 months of therapy the level of microalbuminuria decreased significantly in the study group compared with the control group. Canephron N had a positive effect on the antioxidant defense status and lipid peroxidation levels. In addition, liver aminotransferase levels did not change.
Conclusions:
With respect to the excellent tolerability, the study results encourage use of the herbal combination as an add-on therapy in patients with DN.
... A total of eight eligible controlled studies were found [16,[57][58][59][60][61][62][63]. Four were randomised controlled trials, 1 was counterbalanced and 3 were non-randomised controlled trials. ...
... Three studies examined healthy populations screened for sleep pathology, medications and lack of a sense of smell [58][59][60]. Two populations were sampled from college campuses (mean age of 19-20 years old) [58,59]. ...
... Three studies examined healthy populations screened for sleep pathology, medications and lack of a sense of smell [58][59][60]. Two populations were sampled from college campuses (mean age of 19-20 years old) [58,59]. Arzi et al. [60] provided no recruitment details but the mean age of participants was 28 years. ...
... Thirteen of the studies were randomized controlled trials (RCTs). [20][21][22][23][24][25][26][27][28][29][30][31][32] Lavender essential oil was most frequently studied, with results trending toward a positive effect. 20,21,[23][24][25][26][28][29][30][31][33][34][35][36] A small to moderate benefit of lavender on sleep was found in a systematic review of the literature specific to lavender and sleep. ...
... [20][21][22][23][24][25][26][27][28][29][30][31][32] Lavender essential oil was most frequently studied, with results trending toward a positive effect. 20,21,[23][24][25][26][28][29][30][31][33][34][35][36] A small to moderate benefit of lavender on sleep was found in a systematic review of the literature specific to lavender and sleep. 37 Lavender (Lavandula angustifolia) essential oil was selected for the study intervention based on its documented sedative and hypnotic properties 18 and its safety profile. ...
To compare the effectiveness of lavender (Lavandula angustifolia) and sleep hygiene versus sleep hygiene alone on sleep quantity and sleep quality and to determine sustained effect at two-week follow-up.
A randomized controlled trial with investigator blinding and steps taken to blind the participants.
Participants' usual sleep setting.
Seventy-nine college students with self-reported sleep issues.
The intervention took place over five nights with baseline, postintervention, and two-week follow-up assessments. Both groups practiced good sleep hygiene and wore an inhalation patch on their chest at night. One group wore a patch with 55 μl of lavender essential oil and the other group wore a blank patch.
Sleep quantity was measured using a Fitbit(®) tracker and a sleep diary, and sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI) and the NIH Patient-Reported Outcomes Measurement Information System (PROMIS) sleep disturbance short form.
The lavender and sleep hygiene group demonstrated better sleep quality at postintervention and two-week follow-up (PSQI p=0 .01, <0.001 and PROMIS p=0.04, 0.007, respectively). The sleep-hygiene-only group also demonstrated better sleep quality but to a lesser extent (PSQI p=0.02, 0.06 and PROMIS p=0.03, 0.03, respectively). Additionally, a clinical effect was found for the lavender group at postintervention, along with a significant finding for waking feeling refreshed (p=0.01). Sleep quantity did not differ between groups.
Lavender and sleep hygiene together, and sleep hygiene alone to a lesser degree, improved sleep quality for college students with self-reported sleep issues, with an effect remaining at follow-up.
... Aromatherapeutic essential oils produce physiological and psychological effects, including sleep and mood changes, though most data obtain from case reports and small studies (Buckle, 2001;Gyllenhaal et al., 2000;Price and Price, 1999;Tisserand, 1988). For example, exposure to various essential oils improved sleep-including decreased time awake, increased total sleep time and efficiency and reduced daytime sleepiness-in young, elderly, and demented subjects (Connell et al., 2001;Hardy, 1991;Henry et al., 1994;Hudson, 1996;Raudenbush et al., 2003;Sano et al., 1998;Svoboda et al., 2002;Wolfe and Herzberg, 1996). More recently, lavender, a sedating odor, increased deep or slow-wave PSG sleep in healthy young adults (Goel et al., 2005). ...
... Peppermint increased SWS in those perceiving it as very intense, in contrast with our predictions and other findings reporting stimulating effects of peppermint (Badia et al., 1990;Carskadon and Herz, 2004;Klemm et al., 1992;Norrish and Dwyer, 2005;Stampi et al., 1996;Sullivan et al., 1998;Torii et al., 1988;Warm et al., 1991). This SWS increase in subjects perceiving peppermint as intense, however, corroborates other reports of improved sleep following odor exposure (Connell et al., 2001;Goel et al., 2005;Hardy, 1991;Henry et al., 1994;Hudson, 1996;Raudenbush et al., 2003;Sano et al., 1998;Svoboda et al., 2002;Wolfe and Herzberg, 1996). Therefore, peppermint has sleep-promoting effects in a subset of subjects, underscoring the importance of perceptual odor interpretation. ...
Peppermint, a stimulating odor, increases alertness while awake and therefore may inhibit sleep. This study examined peppermint's effects on polysomnographic (PSG) sleep, alertness, and mood when presented before bedtime. Twenty-one healthy sleepers (mean age +/- S.D., 20.1 +/- 2.0 years) completed three consecutive laboratory sessions (adaptation, control, and stimulus nights). Peppermint reduced fatigue and improved mood and was rated as more pleasant, intense, stimulating, and elating than water. These perceptual qualities associated with sleep measures: subjects rating peppermint as very intense had more total sleep than those rating it as moderately intense, and also showed more slow-wave sleep (SWS) in the peppermint than control session. Furthermore, subjects who found peppermint stimulating showed more NREM and less REM sleep while those rating it as sedating took longer to reach SWS. Peppermint did not affect PSG sleep, however, when these perceptual qualities were not considered. Peppermint also produced gender-differentiated responses: it increased NREM sleep in women, but not men, and alertness in men, but not women, compared with the control. Thus, psychological factors, including individual differences in odor perception play an important role in physiological sleep and self-rated mood and alertness changes.
... Several other studies report improved sleep-including decreased time awake, increased total time asleep, and reduced daytime sleepiness-following lavender presentation before and during sleep in elderly and demented subjects (Hardy, 1991;Henry et al., 1994;Hudson, 1996;Wolfe and Herzberg, 1996). Other essential oils have produced similar effects in young and older adults (Connell et al., 2001;Raudenbush et al., 2003;Sano et al., 1998;Svoboda et al., 2002). However, these studies were uncontrolled, had small sample sizes, and used subjective evaluations. ...
... The predicted SWS increase corroborates previous reports of improved sleep quality following exposure to lavender (Hardy, 1991;Henry et al., 1994;Hudson, 1996;Wolfe and Herzberg, 1996) or other odors (Connell et al., 2001;Raudenbush et al., 2003;Sano et al., 1998;Svoboda et al., 2002). While these earlier studies contained methodological drawbacks, our results demonstrate lavender's sleep-promoting effects using a larger sample and objective sleep measures. ...
Aromatherapy is an anecdotal method for modifying sleep and mood. However, whether olfactory exposure to essential oils affects night-time objective sleep remains untested. Previous studies also demonstrate superior olfactory abilities in women. Therefore, this study investigated the effects of an olfactory stimulus on subsequent sleep and assessed gender differences in such effects. Thirty-one young healthy sleepers (16 men and 15 women, aged 18 to 30 yr, mean+/-SD, 20.5+/-2.4 yr) completed 3 consecutive overnight sessions in a sleep laboratory: one adaptation, one stimulus, and one control night (the latter 2 nights in counterbalanced order). Subjects received an intermittent presentation (first 2 min of each 10 min interval) of an olfactory (lavender oil) or a control (distilled water) stimulus between 23:10 and 23:40 h. Standard polysomnographic sleep and self-rated sleepiness and mood data were collected. Lavender increased the percentage of deep or slow-wave sleep (SWS) in men and women. All subjects reported higher vigor the morning after lavender exposure, corroborating the restorative SWS increase. Lavender also increased stage 2 (light) sleep, and decreased rapid-eye movement (REM) sleep and the amount of time to reach wake after first falling asleep (wake after sleep onset latency) in women, with opposite effects in men. Thus, lavender serves as a mild sedative and has practical applications as a novel, nonphotic method for promoting deep sleep in young men and women and for producing gender-dependent sleep effects.
... Bitter orange odor increased sleep quality in postmenopausal women 8 and improved mothers' sleep quality in postpartum period 9 . Jasmine odor led to greater sleep efficiency and reduced sleep movement 10 . Lavender oil, in turn, enhanced sleep effectiveness, increased total sleep time 11,12 , promoted sleep in patients with insomnia 13 and those having clinical interventions 14,15 . ...
The present study aimed to systematically examine whether laurinal, orange odor, and a specifically designed “perfume” influence sleep quality. During sleep, healthy participants (n = 139) were presented with odor or no odor through nose clips for fourteen consecutive nights (phase one). We collected physiological parameters together with subjective reports. Later on, longer lasting effects of this manipulation were examined for the following fourteen nights (phase two) without exposition to odors. Additionally, olfactory, cognitive and non-cognitive measures were conducted before phase one, between both phases and after phase two. One-way analyses of variance for repeated measures with nights and condition (1 vs 2) as the within-subject factor and odor condition (0, 1, 2 or 3) together with odor pleasantness rating as between-subject factor, was employed to analyse data. Overall, the present results demonstrated that the odor condition in comparison to control had no consistent effect on sleep in healthy participants which can be possibly explained by exposure to odors via nose clips. However, the analyses indicated that the individual pleasantness of odors enhanced the positive assessment of sleep quality. Altogether, the present results indicate that the subjective perception of an odor’s hedonic value appears to be crucial for sleep quality, not the odors themselves.
... La nuit, elles respirent, mais les volumes de gaz carbonique rejetés sont très faibles. A contrario, il est désormais reconnu par exemple que le jasmin et la lavande ont la propriété d'améliorer la qualité du sommeil ainsi que les performances cognitives (Goel, Kim & Lao, 2005 ;Raudenbush, Koon, Smith et al., 2003). Nous l'avons vu, la présence de plantes peut s'avérer relaxante et dépolluante, et cela représente de vrais bénéfices pour nos aînés. ...
... Previous studies showed that lavender aroma contributed to improved sleep quality [2], decreased blood pressure [3,4], and improved task performance [5] and relieved job-related stress [6]. Jasmine odor led to greater sleep efficiency, alertness, mental performance, and reduced sleep movement [7]. Natural essential oil of orange could reduce salivary cortisol and pulse rate [8]. ...
The aim of this study is to investigate the effect of odor on the heart rate (HR) and salivary cortisol levels during sleep at home. Twenty male students (aged 20.9 ± 0.74 years) participated in the study and were exposed to three different odorants (apple, cedar wood, and citrus ginger) or a scentless control sample each night in their home environment in a counterbalanced order. In this within‐subjects study design, all subjects were instructed to sleep at home for 6 h, from 00:00 to 06:00, and HR was measured using a wristwatch‐type HR monitor. Saliva samples were obtained before sleep and after awakening. While subjective sleep quality at awakening did not differ between conditions, tension and anxiety, as assessed by the Profile of Mood State Questionnaire, significantly decreased from the night before sleep to the next morning on which citrus ginger exposure was provided (p < 0.01). Moreover, HR during sleep and after awakening, as well as cortisol secretion after awakening, was significantly higher in the citrus ginger condition (p < 0.01–0.05). Hence, the inhalation of citrus ginger aroma during sleep may enhance sympathetic nervous and endocrine system activity while alleviating psychological tension and anxiety. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
... Empiricky doložené účinky na spánek mají rovněž například cedr (Sano et al., 1998), α-pinen (Yamaoka et al., 2005, jenž se nachází v olejích mnoha druhů jehličnatých stromů, zejména borovic, a podle toho také voní, kozlík lékařský (Komori et al., 2006), který připomíná pach kočičí moči, vetiver (Arzi et al., 2010) nebo růže (Komori et al., 2006). Kupříkladu dopolední odpočinek zdravých jedinců vystavených pachu cedru vykazoval oproti kontrolám kratší latenci NREM 2 (Sano et al., 1998) a odorizace místnosti jasmínem zvýšila efektivitu spánku (Raudenbush et al., 2003). Ostatní data, jež ovšem pocházejí ze studií na krysách, ukazují například, že cedr též prodlužuje trvání NREM spánku (Sano et al., 1998), α-pinen prodlužuje trvání paradoxního spánku v určité části noci (Yamaoka et al., 2005) a kozlík lékařský zkracuje latenci a prodlužuje celkovou dobu spánku (Komori et al., 2006). ...
The association between sleep and chemosensory research represents a seemingly unlikely yet all the more fruitful alliance overlapping with other disciplines, such as cognitive and affective science. Olfactory perception in sleep represents an exception among the sensory modalities in that, in contrast to the other senses, suprathreshold olfactory stimulation does not trigger arousal or waking. Under certain conditions odors can even promote sleep. This promises a wide scope of application in the research context as well as clinical practice. The aim of the study is to outline the characteristics of olfactory processing in sleep and present ways in which they may be utilized in the research of dreams or memory consolidation.
... Peppermint oil was also found to increase total sleep time and decrease fatigue and depression among healthy adults [56]. Jasmine oil was reported to increase sleep efficiency and also to reduce sleep movement [57]. More studies need to be done in humans as far as other essential oils that have proved to be useful to enhance sleep in animals. ...
Prevalence of various types of sleep disturbances have been increasing at an alarming rate in the past few decades and have also been associated with several physiological as well as psychological problems. Pharmaceutical hypnotics have been the first-line of pharmacotherapy to be used for the treatment of such sleep disturbances. However, in the past two decades, complementary and alternative therapies have gained grounds in this field and reviews have been done on some of these therapies. Some of the notable therapies that have been reviewed extensively include homeopathic remedies, ayurvedic preparations, acupuncture and cognitive behavioral therapy. However, the literature lacks an extensive comparative study of the physiological explanations behind these alternative approaches to enhance sleep and this study aims to fill in that gap. Various studies pertaining to alternative approaches to enhance sleep such as nutritional interventions, herbal medicines, essential oils, acupuncture, bright light therapy, music therapy, massage and touch therapies, yoga and tai-chi are reviewed here, thereby providing a potent source of information for both clinicians and patients on these specific alternative therapies to alleviate sleep disturbances. The physiological basics of homeopathy and Ayurveda are beyond the scope of this review. Apart from reviewing the physiological elucidations behind the simpler alternative therapies suggested, their effectiveness over a wide range of people is also reviewed in this study.
... Across a range of studies, odor exposure has been found to affect alertness and vigilance, e.g., [7,8]; for indirect facilitative effects see [50]. A relationship has been found between odor identification ability and resistance of vigilance to sleep deprivation [51]. ...
This paper reviews evidence that, in addition to incidental olfactory pollutants, intentional odor delivery can impact cognitive operations both positively and negatively. Evidence for cognitive facilitation/interference is reviewed alongside four potential explanations for odor-induced effects. It is concluded that the pharmacological properties of odors can induce changes in cognition. However, these effects can be accentuated/attenuated by the shift in mood following odor exposure, expectancy of cognitive effects, and cues to behavior via the contextual association with the odor. It is proposed that greater consideration is required in the intentional utilization of odors within both industrial and private locations, since differential effects are observed for odors with positive hedonic qualities.
Sleep disorders are one of the most prevalent psychiatric diseases. Insomnia is the most common sleep disorder amongst the general population. It is also one of the most frequent complaints in primary healthcare centers. Lavender is called “the broom of the brain” in different oriental traditional medicines. It is one of the most used plants for patients with sleep disorders. This study reviews what is currently known about the use of lavender for sleep disorders in patients with different diseases, from cancers and end‐stage renal disease to neurological‐psychiatric diseases (e.g., depression, dementia, and autism), respiratory, cardiac, and metabolic diseases. Additionally, its most used administration route is the inhalation of its essential oil (i.e., aromatherapy) alone or in combination by massage. Some limitations of the reviewed literature were discussed briefly. Overall, this critical review provides promising evidence of the lavender efficacy for sleep disorders in a wide variety of populations and diseases. However, further clinical studies with robust design and longer durations of intervention are necessary for more evidence‐based judgment on its effect on sleep problems and to investigate its mechanism of action.
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.
Finding a non-pharmacological adjunct to enhance cognitive processing in humans would be beneficial to numerous individuals. Past research has consistently noted a significant interplay between odors and human behavior; for example, the administration of particular odorants enhances athletic performance, mood, and sleep quality. In addition, odorants have a differential effect on human behavior, dependent upon route of administration (retronasal vs. orthonasal). The following study examined the differential effects of odorants on cognition based upon route of administration. During Phase 1, 31 participants completed cognitive tasks on a computer-based program (Impact©) under five "chewing gum" conditions (no gum, flavorless gum, peppermint gum, cinnamon gum, and cherry gum). During Phase II, 39 participants completed the cognitive tasks under four odorant conditions (no odor, peppermint odor, jasmine odor, and cinnamon odor). Results revealed a task-dependent relationship between odors and the enhancement of cognitive processing. Specifically, cinnamon, administered retronasally and orthonasally, improved participants' scores on tasks related to attentional processes, virtual recognition memory, working memory, and visual-motor response speed. Implications are discussed in relation to providing a non-pharmacological adjunct to enhance cognition in the elderly, individuals with test-anxiety, and those with symptoms of dementia.
Smell and taste are our most misunderstood senses. Given a choice between losing our sense of smell and taste, or our senses of sight and hearing, most people nominate the former, rather than the latter. Yet our sense of smell and taste has the power to stir up memories, alter our mood and even influence our behaviour. In The Neuropsychology of Smell and Taste, Neil Martin provides a comprehensive, critical analysis of the role of the brain in gustation and olfaction. In his accessible and characteristic style he shows why our sense of smell and taste do not simply perform basic and intermittent functions, but lie at the very centre of our perception of the world around us. Through an exploration of the physiology, anatomy and neuropsychology of the senses; the neurophysiological causes of smell and taste disorders, and their function in physical and mental illness, Neil Martin provides an accessible and up-to-date overview of the processes of gustation and olfaction. The Neuropsychology of Smell and Taste provides a state-of-the-art overview of current research in olfactory and gustatory perception. With sections describing the effect of odour and taste on our behaviour, and evaluating the contribution current neuroimaging technology has made to our understanding of the senses, the book will be of interest to researchers and students of neuropsychology and neuroscience, and anybody with an interest in olfaction and gustation.
Background:
Lavender inhalation aromatherapy is widely believed to impart a hypnotic effect, act as a mood stabilizer, and enhance the positive feelings of mothers toward their infants. However, research into these and other potential therapeutic effects of lavender tea has been limited.
Aims:
This study was conducted in Taiwan to evaluate the effectiveness of lavender tea in relieving sleep quality, fatigue, and depression; and in improving maternal-infant attachment during the early postpartum period.
Methods:
A total of 80 Taiwanese postnatal women with poor sleep quality (Postpartum Sleep Quality Scale; PSQS score ≥16) and with no history of allergy to herbal teas, foods, or medicines were assigned systematically to either the experimental group (n = 40) or the control group (n = 40). The participants in the experimental group were instructed to drink one cup of lavender tea after spending time to appreciate and smell the aroma each day for a period of 2 weeks, whereas their control group peers received regular postpartum care only. The PSQS, Edinburgh Postnatal Depression Scale, Postpartum Fatigue Scale, and Postpartum Bonding Questionnaire were used to assess outcomes.
Results:
ANCOVA analyses using education level and pretest scores as covariates showed that experimental group participants perceived less fatigue (F = 6.281, p = .014) and depression (F = 4.731, p = .033) and showed greater bonding with their infant (F = 4.022, p = .049) compared with the control group. However, the scores for all four instruments were similar for both groups at the 4-week posttest, suggesting that the positive effects of lavender tea were limited to the immediate term.
Linking evidence to action:
Healthcare researchers assume accountability for integrating research results into clinical practice. The findings in this study can gain greater attention among healthcare practitioners and encourage the correct and positive use of herbal therapy in postpartum health care.
Objective:
Sleep disturbances are recognized as an important health and public health problem that affects physical, mental, and emotional health and well-being. Inhalation of essential oils may be a safe alternative to pharmaceutical interventions for mild to moderate sleep disturbances. Quantitative human studies on the effect of inhaled essential oils on sleep that were published between 1990 to 2012 were reviewed.
Methods:
Ovid Medline, PsychINFO, CINAHL, Science Direct, and PubMed databases were searched to extract articles that evaluated the effect of inhaled essential oils on sleep in humans.
Results:
The search yielded 15 quantitative studies, including 11 randomized controlled trials that examined hypnotic effects of inhalation of essential oils. A majority of the study findings suggested a positive effect of essential oils on sleep. Lavender was the most frequently studied essential oil. No adverse events were reported.
Conclusions:
Inhalation of essential oils may be considered for people with mild sleep disturbances. Further studies with larger samples and stronger methods and endpoints are needed to build on the findings.
The purpose of this study was to assess the effects of water, lavender, or rosemary scent on physiology and mood state following an anxiety-provoking task. The nonsmoking participants, ages 18-30 years, included 42 women and 31 men who reported demographic information and measures of external temperature and heart rate were taken prior to introduction of an anxiety-eliciting task and exposure to lavender, rosemary, or water scents. Following the task, participants completed the Profile of Mood States to assess mood, and temperature and heart rate were reassessed. Participants rated the pleasantness of the scent received. When pleasantness ratings of scent were covaried, physiological changes in temperature and heart rate did not differ based on scent exposure, but mood ratings differed by scent condition. Participants in the rosemary condition scored higher on measures of tension-anxiety and confusion-bewilderment relative to the lavender and control conditions. The lavender and control conditions showed higher mean vigor-activity ratings relative to the rosemary group, while both rosemary and lavender scents were associated with lower mean ratings on the fatigue-inertia subscale, relative to the control group. These results suggest that, when individual perception of scent pleasantness is controlled, scent has the potential to moderate different aspects of mood following an anxiety-provoking task.
In aromatherapy, lavender aroma is reputed to assist with relaxation. However, while there is much anecdotal evidence to that effect, the empirical literature is very inconsistent. Failure to employ adequate placebos, proper blinding, objective measures, or screening of prior beliefs about aromatherapy means that many previous findings could have been influenced by expectancy biases. The present study sought to establish whether lavender aroma and/or expectancies affect post-stress relaxation.
A double-blind, 3 (aroma) x 3 (instruction) x 10 (time in minutes) mixed-factorial placebo-controlled trial.
In a laboratory, 96 healthy undergraduate women were exposed to lavender, placebo, or no aroma during physiologically assessed relaxation after an arousing cognitive task. Where an aroma was presented, an instructional priming procedure was used to manipulate participants' expectancies about the aroma's likely impact on their ability to relax.
Results showed no effect of aroma on galvanic skin response during relaxation. However, the nature of instructional prime was associated with relaxation patterns: when expecting the aroma to inhibit them, participants relaxed more; when expecting facilitation, participants relaxed less. The effect was not seen with regard to self-reported relaxation (as represented by changes in state anxiety) and was independent of ratings of attitudes towards aromatherapy.
The findings imply that the previous associations of lavender aroma with assisted relaxation may have been influenced by expectancy biases, and that the relevant expectancies are easily manipulable.
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