TITLE:
Acute Effects of Aroma Exposure and Breathing Patterns on Physiological Responses: A Controlled Experimental Study
AUTHORS:
Yui Kikuchi, Yumi Fukuyama, Sho Kumabe, Akihiro Takada, Suguru Ando, Masaki Iwamura, Emiko Morita, Yoshihiro Yamashina
KEYWORDS:
Aromatherapy, Breathing Pattern, Vagal Stimulation, Autonomic Nervous System, Acute Effect, Lavender
JOURNAL NAME:
Open Journal of Therapy and Rehabilitation,
Vol.14 No.1,
December
26,
2025
ABSTRACT: Purpose: Aromatherapy has been reported to improve mood, reduce stress, and stabilize autonomic nervous system (ANS) activity. However, it remains unclear whether these acute physiological effects are caused by aroma itself or by accompanying changes in breathing patterns. Participants and Methods: This study aimed to differentiate the acute effects of aroma and breathing patterns on cardiovascular and stress-related indices in healthy adults. Twenty participants completed a randomized crossover trial with four conditions: 1) aroma + normal breathing, 2) aroma + deep breathing, 3) no aroma + normal breathing, and 4) no aroma + deep breathing. Lavender essential oil (1%) was sprayed twice per minute for 5 min, while 10% ethanol served as the control. Breathing patterns were guided and monitored using a respiratory gas analyzer. Heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressure, and salivary amylase (SA) were measured before and after each condition. Results: HR, SBP, and SA significantly decreased under deep-breathing conditions, independent of aroma exposure. No significant main effects of aroma or interaction effects were observed. DBP showed no significant changes across any condition. Conclusion: The acute physiological benefits observed were primarily attributed to breathing patterns rather than aroma exposure, suggesting that relaxation effects ascribed to aromatherapy may reflect vagal activation induced by deep breathing. These findings do not imply that aroma lacks effectiveness; rather, they indicate that during short-term exposure, vagal activation induced by deep breathing plays a dominant role in reducing autonomic arousal. As aroma may facilitate deeper breathing and its chronic effects have been demonstrated in previous studies, the present findings should be interpreted within the context of acute physiological responses only.