The influence of social or task-oriented horticultural classes on adrenal-immune axis responses, emotions, and common cold symptoms in female university students

This study investigated the changes in adrenal-immune axis activation, affective responses, and upper respiratory infection (URI) symptoms, and group cohesion of 24 female university students who enrolled in horticultural classes. Fourteen students from a horticultural laboratory (LAB) class and 10 from a landscape lecture (LEC) class were asked to provide saliva samples and information on demographics, group cohesion, affective responses, health behaviors, and URI symptoms, weekly for 12 weeks. The LAB group completed projects such as plant propagation, indoor gardening and floral design during a 40-minute laboratory. The LEC group listened to 40-minute horticultural lectures at the same time.; The average level of salivary cortisol across the nine weeks tended to be lower in the LAB group (p < 0.03) with higher concentrations of secretory immunoglobulin A (sIgA) (p < 0.02) as compared to the LEC group. However, there were no significant group and week effects of the 40-min session on changes of cortisol and sIgA. In response to each session, students in the LAB group tended to have consistently increased positive emotions, while students in the LEC group decreased or showed no change. Over 12 weeks, there were no significant differences in total number and severity of URI symptom, and perceived stress between the groups. Initially, social and task attractions as a group were higher in the LAB class, as compared to the LEC class. After 12 weeks, the LEC group had slightly increased the overall attraction to task and social involvement. Correlations were higher between social integration and task perception in the LAB group at the end.; This study found that active horticultural activities (LAB) increased positive emotions and group interactions more than passive lectures (LEC). Plant interactions designed in an active form may influence the adrenal-immune axis to produce a restorative effect in stress intervention and holistic health.