Mind-body interactions are important in functional somatic syndromes (FSS). Therefore, in the assessment of the psychophysiological stress response in patients with FSS, both subjective feelings and psychophysiological activity should be simultaneously measured. In this study, "Objective Tension Score" (OTS) was defined as an objective parameter of tension; it consisted of surface electromyography and skin conductance level as indicators of muscle and mental tension, respectively. "Subjective Tension Score" (STS) was defined as a subjective parameter of tension. Changes in OTS and STS in response to the stress task were investigated in 30 FSS patients and 28 controls. Objective tension was significantly hyporeactive to the stress task and STS was significantly higher in the patient group than in the control group. There was a significant negative correlation between OTS response and STS in the patient group, but no significant correlation in the control group. Our results suggested the existence of dissociation between subjective and objective responses in FSS patients. This may indicate that FSS patients had difficulty with the awareness of bodily feelings, thus supporting the concept of "alexisomia" or "escaped bodily feelings" in FSS patients.