The impact of tea aroma inhalation has not been as extensively researched as the effect of tea drinking with various mental health benefits. As published in a recent study in the Journal of Physiological Anthropology, a team of researchers at the University of Shizuoka, Chubu University, Mitsui Norin Co., Ltd, and Tokai University in Japan has determined that breathing in the scent of black tea may decrease stress levels before and after a mentally demanding competition.
Eighteen healthy people aged between 20 and 21 years participated in the study which evaluated the relieving effects of two kinds of black tea (Assam and Darjeeling) aromas on physical and cognitive stress. The participants were advised to not consume anything except water for three hours before the beginning of each trial. Then, the team induced stress in the participants using a psycho-diagnostic test called Uchida-Kraepelin test, which involves solving a series of mathematical problems within 30 minutes (split into two 15-minute sessions). In between sessions, the attendants were tested either by inhaling either black tea aroma or were presented with warm water for one minute’s duration. After each of these periods, the research team used degrees of salivary chromogranin-A (CgA) (an acidic protein created in response to stress) as a stress marker to classify the influence of inhaling black tea aroma in the members of the study.
Based on the outcome, those participants who inhaled black tea aroma presented lower salivary CgA accumulation levels after 30 minutes of mentally stressful exercises compared to those who were exposed to warm water only.
Surprisingly, both black teas caused identical effects, despite the fact that Darjeeling tea aroma contains a higher aggregation of anti-stress components, such as hexanal, hexanol, and linalool, when set side by side with Assam black tea. Hexanal and hexanol have alreadly been documented to reduce mental stress response in trials with mice, while linalool has soporific effects.
“The above results indicated that inhaling black tea aroma may diminish stress levels caused by arithmetic mental stress tasks, and Darjeeling tea aroma tended to improve (the) mood before mental stress load,” wrote the research team.
The researchers continued: “Another factor to consider for future studies could be to explore gender differences in the anti-stress effects of black tea aroma, for which more male participants may be needed.”
“It will also be interesting to compare this data with other kinds of tea odors by multiple indexes of autonomic nervous system and central nervous system and activities.”