Essential oil inhaler (AromaStick®) improves heat tolerance in the Hot Immersion Test (HIT). Results from two randomized, controlled experiments

Abstract

Background: A recent review article on an aromatherapeutic inhaler demonstrated clinical effects on a number of bodily systems, like the cardiovascular system, the respiratory system, the nervous system and the endocrine system.

Objective: This paper extends these findings and investigates whether specially designed essential oils inhalers are capable to counter experimentally induced stressful heat sensations.

Method: Two prospective, randomized, controlled experiments using the Hot Immersion Test Paradigm (HIT) were conducted to investigate whether deep odor inhalations increase heat tolerance.

Results: In both experiments, the inhaler strongly prolonged pain tolerance and increased blood oxygenation (1 < d < 1.3). In the second experiment, the inhaler also increased heart rate variability (d = 1.3) as a mechanism to cope with heat stress.

Conclusion: The ability to resist a stressful thermal stimulus can be exogenously improved by short and deep inhalations of essential scents directly delivered to the olfactory system.

Keywords: AromaStick®; Blood oxygenation; Essential oil inhaler; Heart rate; Heat pain tolerance; Hot Immersion Test (HIT).