Associations Between Autonomic Nervous System Activity, Cerebral Blood Flow, and Essential Oil Preferences Across the Menstrual Cycle

Abstract

Introduction: Essential oil preferences, which vary depending on an individual's physical and mental conditions, may trigger various emotions and affect autonomic nervous system (ANS) function and cerebral blood flow. This study aimed to investigate the relationship between essential oil preference during the menstrual cycle, ANS activity, and cerebral blood flow during a sniffing exercise. Methods: An observational study integrating aromatherapy with slow-paced breathing was conducted. Eighteen women (aged 20–22 years) without olfactory impairments were categorized into two groups: those with strong symptoms perceived in the late luteal phase (n = 10) and those with mild symptoms (n = 8). The study assessed responses during the early follicular and late luteal phases and recorded preferences for the following four essential oils: pine sylvestre (Pinus sylvestris), geranium bourbon (Pelargonium X asperum), lemongrass (Cymbopogon flexuosus), and lavender vera (Lavandula angustifolia). The autonomic nervous activity and cerebral blood flow were assessed in the early follicular and late luteal phases using the essential oils most and least preferred by each participant. Results: Participants with stronger symptoms in the late luteal phase appeared to prefer lemongrass and dislike pine sylvestre, whereas those with milder symptoms in the late luteal phase preferred lavender vera and disliked lemongrass. Changes in ANS activity, marked by an increase in sympathetic function and a decrease in parasympathetic function during the sniffing exercise, persisted regardless of the menstrual cycle stage or essential oil preference. The inhalation of preferred essential oils stimulated cerebral blood flow, whereas less-preferred oils led to a reduction. Conclusion: Essential oil preference in young women may be influenced by subjective symptoms during the menstrual cycle. Furthermore, essential oil preference affects cerebral blood flow. These findings have potential implications for aromatherapy practice.

Keywords

• essential oil
• preference
• menstrual cycle
• autonomic nervous activity
• cerebral blood flow
• sniffing exercise