According to a study published in the journal Nutrients by M. Fukatsu, Y. Tsuchiya, and Y. Inoue, short-term exposure to the aroma of coffee leads to measurable reductions in negative mood dimensions and slight increases in relaxation-related electroencephalographic activity among young adults, though cardiovascular and autonomic signals show no statistically significant changes.
Evaluating the Multi-Modal Response to Coffee Aroma
Researchers at Showa Pharmaceutical University tracked mood, brain activity, heart rate, and autonomic signals in the same group of young adults to examine how the mind and body respond to just five minutes of coffee aroma. The study, conducted between March 2024 and March 2026, involved twenty healthy participants aged 20-29 years, consisting of 8 men and 12 women. For each experiment, freshly brewed coffee was placed approximately 50 cm from the participants. They were exposed continuously to the aroma for 5 min while breathing normally in a ventilated room.
Did you know?
The study utilized a multi-modal approach to assess psychological and physiological changes simultaneously, helping researchers understand how different domains interact during olfactory stimulation.
Previous research has investigated responses in mood, salivary cortisol, and working memory to exposure to coffee aroma. Prior investigations have generally concentrated on isolated response categories, making it difficult to evaluate how shifts manifest when evaluating several areas at once within a single participant. The authors of the Nutrients paper noted that responses across physiological and psychological domains need not necessarily occur in tandem, making a multi-modal evaluation necessary for a complete characterization.
Mood State Reductions and EEG Relaxation Indices
Subjective mood was assessed immediately before and after exposure using the Profile of Mood States (POMS). According to the findings, Total Mood Disturbance (TMD) decreased following the exposure. Reductions were also observed in the Tension–Anxiety, Anger–Hostility, Fatigue, Confusion, and Depression–Dejection subscales. However, after adjustment for multiple comparisons, the reduction in Anger–Hostility was no longer statistically significant, and Vigor showed no statistically significant change.
In tandem with psychological assessments, EEG activity was analyzed using alpha (α), beta (β), and theta (θ) frequency components. The study revealed that the EEG-derived relaxation index rose from about 0.74 pre-exposure to 0.78 post-exposure. While this change was modest, it was consistent across participants. The authors caution that this index reflects relaxation-related EEG activity rather than directly measuring relaxation, and its physiological significance has not been established.
Cardiovascular Monitoring and Exploratory Correlations
Heart rate and autonomic signals were tracked using portable and wearable devices. Heart rate measurements showed no statistically significant pre–post differences, aligning with some existing research. Similarly, heart rate variability—assessed using the low-frequency/high-frequency (LF/HF) ratio—revealed no statistically significant shifts.
Exploratory Pearson correlation analyses conducted by the researchers revealed no statistically significant associations between changes in mood, EEG activity, HR, and HRV. Consequently, the authors caution that concurrent group-level changes should not be interpreted as evidence of a common underlying mechanism across these different domains.
Pro Tip for Researchers
Concurrent multi-modal assessments capture complementary but distinct aspects of the response to coffee aroma, pointing to the value of broad physiological monitoring in future sensory studies.
Study Limitations and Future Research Directions
The exploratory within-subjects design carries distinct limitations. Most notably, the study lacked a control condition, so the results cannot be causally attributed to exposure to coffee aroma. Factors such as time, quiet rest, repeated measurement, expectation, adaptation to the experimental environment, or other nonspecific variables could potentially have played a role in the observed modifications.
In addition, the limited participant count restricts the accuracy of the point estimates, while restricting the cohort solely to healthy adults aged 20-29 years restricts how broadly the results can be applied. Furthermore, the investigation failed to systematically evaluate regular coffee intake, coffee preferences, familiarity with the aroma, or olfactory sensitivity, and omitted quantitative tracking of airflow or aroma concentration. Furthermore, the consumer-grade EEG device also has technical limitations compared with laboratory-grade EEG equipment.
Frequently Asked Questions
What did the study measure during coffee aroma exposure?
Researchers measured subjective mood via the Profile of Mood States, electroencephalographic activity, heart rate, and heart rate variability in twenty healthy adults.
How long were participants exposed to the coffee aroma?
Participants were exposed continuously to the aroma for 5 min while breathing normally.
Did the coffee aroma cause significant changes in heart rate?
No, HR and HRV measurements showed no statistically significant pre–post differences.
Can these changes be definitively blamed on the coffee aroma?
Not yet. Given the absence of a control group in the study, the observed modifications may have been influenced by time, quiet rest, repeated measurement, expectation, adaptation to the experimental environment, or other nonspecific factors.
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