The researchers chose lemon and lavender since they were two of the most popular scents tied to aromatherapy. Recently, two other studies focused on these same two scents. For the study, Janice Kiecolt-Glaser, professor of psychiatry and psychology at Ohio State University and colleagues assembled a group of 56 healthy volunteers. These men and women were screened beforehand to confirm their ability to detect standard odors. Some were proponents of the merits of aromatherapy while others expressed no opinion on its use.
Each person took part in three half-day sessions where they were exposed to both scents. Participants were monitored for blood pressure and heart rate during the experiments, and the researchers took regular blood samples from each volunteer. They taped cotton balls laced with either lemon oil, lavender oil or distilled water below the volunteers’ noses for the duration of the tests.
The researchers tested volunteers’ ability to heal by using a standard test where tape is applied and removed repeatedly on a specific skin site. The scientists also tested volunteers’ reaction to pain by immersing their feet in 32-degree F water. Lastly, volunteers were asked to fill out three standard psychological tests to gauge mood and stress three times during each session. They also were asked to record a two-minute reaction to the experience which was later analyzed to gauge positive or negative emotional-word use.
The blood samples were later analyzed for changes in several distinct biochemical markers that would signal affects on both the immune and endocrine system. Levels of both Interleukin-6 and Interleukin-10 – two cytokines – were checked, as were stress hormones such as cortisol, norepinephrine and other catacholomines. While lemon oil showed a clear mood enhancement, lavender oil did not, the researchers said. Neither smell had any positive impact on any of the biochemical markers for stress, pain control or wound healing.
MEDICA.de; Source: Ohio State University