Influences of foliage plants on human stress during thermal biofeedback training

Twelve 20-minute thermal biofeedback sessions were conducted with 26 university students. Visual stimuli were provided by a living foliage plant, a life-sized color photograph of that plant, or a metal stool (control). Of the participants, 38% responded positively to the presence of a live plant or plant photograph, while 23% showed lower stress in the control room. Stress reduction, as indicated by higher skin temperatures, occurred within the first 5 to 8 minutes of a 20-minute thermal-biofeedback session. A nonplant visual stimulus was not part of the experiment. The results are not intended as comparative, nor do they attribute unique or superior effects to plants. Due to the small number of participants, no significant results were obtained, but the trends were important and are being reported to help further research in this area.