When you encounter a scent you like, you may find yourself wanting to smell it slowly once more. Time spent enjoying fragrance may involve not only the impression through your nose but also the way you breathe.
In October 2025, Valentin Ghibaudo and colleagues at the Lyon Neuroscience Research Center in France published a study using individually preferred odors and music to examine breathing, heart activity, EEG, and subjective feelings simultaneously. They wanted to test whether pleasant odors slow breathing, whether that change is linked to cardiac and brain rhythms, and whether equally pleasant music produces similar responses.
Not everyone was given the same scent
Thirty healthy adults aged 19–51 participated. On the first day, they evaluated 10 odors prepared by a perfumer and 10 pieces of music, then selected the one of each that they found most pleasant. The odors were fragrance mixtures with names such as Rose, Vanilla, and Peach Lavender.
The next day, participants sat resting in a chair with their eyes open. The first 10 minutes were a baseline condition with neither odor nor music. They then experienced their selected odor and selected music for 10 minutes each. The order of odor and music was randomized, with a 15-minute break between them.
Odors were presented in small vials containing beads soaked in an odorant solution, positioned about 10 centimeters from the nose. Responses were recorded using a nasal-airflow sensor, an electrocardiogram, and scalp EEG. After each condition, participants also reported their current feelings of relaxation and arousal.
Breathing cycles became longer in the odor condition
The average time for one complete inhalation and exhalation was approximately 4.71 seconds at baseline and 5.41 seconds in the odor condition. Breathing was slower when the odor was present. In the music condition, the cycle was approximately 4.14 seconds: in this experiment, breathing instead became faster.
The ECG measurements also differed. The interval between successive heartbeats increased from approximately 811 milliseconds at baseline to approximately 830 milliseconds in the odor condition. A longer interval corresponds to a slower heart rate. The music condition did not differ significantly from baseline.
A measure of heart rate variability, the beat-to-beat variation in these intervals, also increased in the odor condition. The researchers discuss these changes as responses involving breathing and autonomic activity. However, an increase in heart rate variability cannot simply be reinterpreted as improved health or relief from stress.
Looking at brain activity that changes with breathing
The researchers also aligned and averaged EEG signals across respiratory cycles to examine recurring changes during inhalation and exhalation. In the odor condition, respiration-related EEG changes were larger than at baseline across several electrodes over the sides and parietal-central regions of the head.
Longer respiratory cycles were also associated with larger respiration-related EEG changes. Some electrodes showed changes in the music condition too, but not the same widespread pattern as in the odor condition. The authors emphasize the possibility that changes in breathing while smelling an odor link rhythms in the body and brain.
These changes do not mean that the performance of the whole brain improved or that the brain rested. The study measured the correspondence between breathing and EEG, not improvements in memory or concentration. Nor did it deliberately manipulate breathing to establish the causal sequence; the proposed mechanism therefore includes hypotheses.
Differences in subjective relaxation were not clear
What about the relaxation participants themselves reported? Mean ratings converted to a 0–1 scale were 0.64 at baseline, 0.72 with music, and 0.75 with odor. Although numerically higher, the difference among the three conditions was not statistically significant.
This does not mean that no one felt more comfortable. It means that, with this sample size and measurement method, a change in relaxation attributable to the conditions was not demonstrated clearly. Physiological changes alone do not establish an increase in subjective relaxation.
Arousal, meaning how activated participants felt, increased above baseline in both odor and music conditions, with a larger increase for music. Liking something and feeling quietly calm were not necessarily experiences moving in the same direction.
The authors suggest that participants’ relatively relaxed initial state and the use of a single question to measure relaxation may have contributed. Even though preferred odors were selected, they were not standardized as either calming or uplifting.
How far can this apply to everyday fragrance?
A distinctive feature of this experiment is that the researchers established personal preferences rather than giving everyone an odor assumed to be generally pleasant. Measurable changes in breathing and heart activity under those conditions offer concrete clues for understanding the experience of enjoying a scent.
However, baseline always came first, so effects of time or becoming accustomed to the experiment cannot be fully separated. Unpleasant or neutral odors were not compared either, so further work is needed to establish how much of the change is specifically attributable to liking the odor.
The study involved 30 people and 10-minute conditions. It did not treat symptoms such as anxiety or insomnia, establish long-term health benefits, or demonstrate effects of a particular commercial perfume. Music results could also differ with the selection method or listening context, so this is not a ranking that places fragrance above music.
Summary
Experiencing a scent may involve not only nasal pleasantness but also connections between bodily and brain rhythms through breathing. The authors regard the slower breathing and changes in cardiac and respiration-related EEG activity under the pleasant-odor condition as clues to this possibility. The absence of the same widespread response to equally pleasant music was another reason to focus on olfaction. However, the causal sequence in which breathing might produce other changes, and any health benefits, have not been established.
Because subjective relaxation did not clearly differ between conditions, one way to read the study is to distinguish measurements from personal experience when enjoying fragrance. Is it pleasant, quietly calming, or a little uplifting? The study did not test the effectiveness of this approach to enjoying scents, but it offers a perspective for paying closer attention to one’s own experience.
References
Authors: Valentin Ghibaudo, Matthias Turrel, Jules Granget, Maëlys Souilhol, Samuel Garcia, Jane Plailly, Nathalie Buonviso
Article: Pleasant odors specifically promote a soothing autonomic response and brain–body coupling through respiratory modulation
Journal: Scientific Reports 15, 36417 (2025)
Published: 17 October 2025
DOI: 10.1038/s41598-025-20422-x
Full text: Publisher’s article page
Original article license: CC BY 4.0
