This preliminary investigation revealed that both aromatherapy and control massage were beneficial for inducing relaxation by decreasing state anxiety levels. Even though trait anxiety scores did not change, state anxiety scores were lowered significantly, This is because the ‘state anxiety’ score represents a temporary condition that changes every moment, while the ‘trait anxiety’ score represents a more general and long-standing quality of anxiety. However, we did not observe any difference between aromatherapy and control massage.
As in the present study, STAI has also failed to detect any difference in psychological results between aromatherapy massage and control massage in other studies. To compare the extent of relaxation after massage and aromatherapy massage in future studies, it might be useful to apply other measurements such as the Rotterdam Symptom Checklist (RSCL), which has demonstrated differences in the psychological and physiological functions of the two types of massage (22
). Furthermore, we did not observe any change of SDS scores before and after massage. This might mean that unlike a state of anxiety, depression does not change instantly. It would be interesting to perform massage several times and examine its long-term effect on depression.
In this preliminary study, a significant decrease in hematocrit was observed after the control massage. In our previous study, massage therapy caused a similar hemodilution (26
). This phenomenon may happen because of a relative parasympathetic nervous system dominant state. On the other hand, the lack of statistically significant hemodilution after aromatherapy massage may have been due to the diuretic effect of essential oils, especially cypress (1
). This difference in hemodilution between aromatherapy massage and control massage was not statistically significant by ANOVA.
With regard to immune measures, a significant increase in numbers of total, CD8+ and CD16+ lymphocytes was observed after aromatherapy massage, but not after control massage. In particular, the increase in CD8+ cell counts after aromatherapy massage was significantly larger than the change in the cell counts after control massage.
A meta-analytic review on psychological interventions and the immune system revealed a significant increase in total lymphocyte numbers with stress management intervention (27
). The same review, however, reported that there were no significant changes in natural killer (NK) cells and lymphocyte numbers after the use of relaxation techniques including biofeedback-assisted relaxation, progressive muscle relaxation and relaxation response. In the case of HIV-positive patients, Ironson et al
. reported that twenty 45 min massages in 1 month or twice a week for 12 weeks significantly increased NK cell numbers and cytotoxicity (9
There is no consistent view about how relaxation influences lymphocyte counts and NK cell numbers, and it is difficult to interpret changes in lymphocyte counts observed in the present study. One possibility is that a difference in the extent of relaxation between aromatherapy massage and control massage results in this divergence. In the present study, the serum cortisol level was reduced significantly after aromatherapy massage, but not after control massage. Although the difference in cortisol levels between aromatherapy massage and control massage was not statistically significant by ANOVA, this result partly supports the above hypothesis in terms of stress hormone reduction. Another possibility is the pharmacological benefit of essential oils. Indeed, almost all of the essential oils used are known to stimulate the function of WBCs (28
In our preliminary study, both aromatherapy massage and control massage decreased state anxiety significantly, and only aromatherapy massage (P < 0.05) increased PBLs, possibly due to an increase in CD8+ and CD16+ lymphocytes. These results suggest that aromatherapy massage is a valuable relaxation technique for reducing anxiety and stress, and beneficial to the immune system. Since this study was done on a small number of patients and examined over a short period, it is important to validate the results in a phase I or II trial with a larger cohort of patients over a longer period of time.