Alleviation of acute stress response by black pepper (Piper nigrum) aroma administration

Abstract

Black pepper is a popular spice globally. Black pepper essential oil could be beneficial in aromatherapy under stressful conditions. This study examined the effect of black pepper aroma on cardiac and peripheral autonomic nervous system (ANS) activity under stressful conditions using an olfactometer to administer aroma in a precise and controlled manner to ensure reproducibility. A within-participant design experiment was conducted with 20 male students who performed a 30 min calculation task as a short-term stressor under three aroma conditions: black pepper, ginger, and dipropylene glycol (DPG). Electrocardiograms and skin conductance level (SCL) were measured for evaluating the physiological acute stress response on ANS. Subjective evaluations and impressions on the types of aroma were assessed. The physiological acute stress response induced by the short-term stressor, which is characterized by the enhancement of the heart rate (HR) and SCL and decreases in the heart rate variability (HRV), was significantly suppressed with black pepper than with DPG(p =0.048, HR and p = 0.002, HRV) and ginger (p = 0.005, SCL); however, there was no significant difference in subjective scores among the conditions. Although black pepper is a stimulative agent, the findings showed that it alleviated the physiological acute stress response.