Background: With growing evidence linking job stress to illness, fi nding an effective means of stress management has become a challenging international endeavor. Although music therapy has attracted the attention of various fi elds as a promising method for alleviating stress, lack of standardization and paucity of data have served as impediments to widespread utilization.
Material/Methods: The effects of a Recreational Music-Making (RMM) group drumming protocol was evaluated on Japanese male corporate employees. A total of 20 volunteers participated in a one-hour RMM session while 20 volunteers engaged in leisurely reading for one hour (controls). After a six-month interval, the groups switched activities and underwent one session each. Pre- and post-intervention data were collected using mood state questionnaires and blood samples. Individual and group mean values for natural killer (NK) cell activity, NK cell percentage, and cytokine gene expression were analyzed.
Results: NK cell activity in the RMM group increased among individuals with low pre-intervention levels, and decreased among those with high pre-intervention levels. A signifi cant correlation was established between changes in NK cell activity and the changes in the level of gene expressions for interferon- γ and interleukin-10. The RMM group demonstrated enhanced mood, lower gene expression levels of the stress-induced cytokine interleukin-10, and higher NK cell activity when compared to the control.
Conclusions: Based upon documented changes in NK cell activity, coupled with gene expression changes for interferon-γ, interleukin-10, and improved mood, this RMM protocol has signifi cant potential for utilization in the corporate wellness environment.

Keywords: Affect - physiology, Cross-Over Studies, Cytokines - genetics, Interferon-gamma - genetics, Interleukin-10 - genetics, Japan, Killer Cells, Natural - immunology, Music - psychology, Recreation