Effect of aromatherapy on autonomic nervous system regulation with treadmill exercise-induced stress among adolescents

Abstract

Introduction Stress is a major health issue in adolescents owing to the important transitions experienced during this period. Aromatherapy is an effective method for the reduction of stress in adolescents. Purpose The aims of this study were to examine the effect of aromatherapy on the regulation of the autonomic nervous system (ANS) along with stress relief and to explore the effect of aromatherapy on adolescents with different levels of stress. Methods This quasi-experimental study comprised three types of treatments: control (no essential oil), pure essential oil therapy (sandalwood), and blended essential oil therapy (sandalwood-lavender). The heart rate variability (HRV) was calculated to evaluate the post-exercise recovery of the ANS to the baseline level in the recruited adolescents. To examine the efficiency of aromatherapy, Friedman test was used to assess the significance of difference in all parameters (i.e., mean heart rate, SDNN, normalized LF, normalized HF, and LF/HF) between baseline and after exercise among the three treatment conditions. Results The participants comprised 43 junior college students (8 males and 35 females) with a mean age of 18.21 ± 0.99. Significant differences in changes of two HRV parameters (normalized LF and LF/HF) were associated with both essential oil therapies compared to those in the control group (p<0.05), and one more HRV parameter (normalized HF) exhibited significant difference related to blended essential oil therapy compared to that of the control group. Besides, changes in two HRV parameters (mean heart rate and normalized HF) of both essential oil therapies in the low level stress subgroup showed significant differences compared to those of the control group (p<0.05). Conclusions This study demonstrated that aromatherapy could be used for ANS regulation with stress-relieving effects in adolescents. The participants with a low stress level appeared to respond better to the blended essential oil therapy, whereas those with medium to high levels of stress appeared to respond poorly to aromatherapy compared to the control.

Relaxing effects of music and odors on physiological recovery after cognitive stress and unexpected absence of multisensory benefit

“…Whether and how music or odor may alleviate stress is a topic that has received considerable interest from researchers since decades (e.g., music, Chafin et al, 2004; Davis & Thaut, 1989; Hernandez‐Ruiz et al, 2020; Linnemann et al, 2015, 2016; Nilsson, 2009; Salamon et al, 2003; Spence & Keller, 2019; odors, Aćimović, 2021; Kang et al, 2019; Lin et al, 2021; Toda & Morimoto, 2008; Warren et al, 1987; Warren & Warrenburg, 1993). Relaxing effects of music listening and odor on physiology have been described using various measures, for example, blood pressure (BP), heart rate (HR), respiration rate (RR), heart rate variability (HRV), and electrodermal activity (EDA) (e.g., for music see Bernardi et al, 2006; Bretherton et al, 2019; Burns et al, 1999; Ellis & Thayer, 2010; Latha et al, 2014; for odors see e.g., Field et al, 2005; Lin et al, 2021; Motomura et al, 2001; Nakanishi et al, 2021; Painchault et al, 2020). All these physiological parameters are governed by the Autonomic Nervous System (ANS).…”

“…Two branches compose the ANS, the sympathetic nervous system (SNS), which increases metabolic activity to trigger the “fight or flight” response, and the parasympathetic nervous system (PNS), which is responsible for restorative activity, commonly called the “rest and digest” response. Thus, when a high level of physiological arousal is required, for instance when individuals are under stress or when they exercise (see Jia et al, 2016; Lin et al, 2021), SNS predominates and is characterized by an increase in EDA, HR, and BP, and a decrease in HRV (Ellis & Thayer, 2010). On the contrary, PNS predominates when individuals are relaxed (Sakakibara et al, 1994), which translates into a decrease in EDA, HR, BP, and an increase in HRV.…”

“…Moreover, pleasantness negatively correlated with HR, indicating that HR increased as the pleasantness of the odor decreased. Lavender essential oil (and its main chemical components linalool and linalyl acetate) has probably been the most popular odorant when investigating the relaxing effects of odor on physiology (e.g., Chamine & Oken, 2015, 2016; Cho et al, 2017; Diego et al, 1998; Field et al, 2005; Kuroda et al, 2005; Lin et al, 2021; Malcolm & Tallian, 2017; Motomura et al, 2001; Sayorwan et al, 2012; Toda & Morimoto, 2008; for reviews see Herz, 2009; Hur et al, 2014; Kang et al, 2019; Sayed et al, 2020). Several studies have reported a decrease of HR when exposed to lavender odor (Cho et al, 2017; Kuroda et al, 2005; Sayorwan et al, 2012), even though it has been claimed that participants' expectations might explain these effects (Campenni et al, 2004; Chamine & Oken, 2015; Howard & Hughes, 2008, but see Baccarani, Grondin, et al, 2021).…”

“…Lavender odor was further reported to provide evidenced beneficial effects on ANS in physiological recovery paradigms (Chamine & Oken, 2016; Chang & Shen, 2011; Field et al, 2005; Lin et al, 2021; Toda & Morimoto, 2008). Toda and Morimoto (2008) reported that chromogranin A, a salivary endocrinological stress marker, increased after performing an arithmetic task and decreased significantly during a 10‐min recovery period but only when lavender odor was presented compared to the control group (no odor).…”

Psychological and neurophysiological effects of inhaled aromatherapy

“…The HRV was also analyzed in junior university students after intervention with lavender essential oil combined with sandalwood essential oil. Aromatherapy intervention appears to reduce stress among adolescents, however, participants with a low level of stress appeared to respond better to combination therapy with essential oil, while those with medium to high levels of stress appeared to respond poorly to aromatherapy compared to the control group (Lin et al, 2021). Pain reduction during the premenstrual period was also observed in young women (Matsumoto, Asakura & Hayashi, 2013).…”