Clinical effects of blood pressure biofeedback treatment on hypertension by auto-shaping.

OBJECTIVE: Although biofeedback has been reported to be efficacious in the treatment of hypertension, the degree of response has varied. This study investigated the mechanisms of blood pressure reduction by biofeedback. METHOD: Thirty outpatients with essential hypertension (10 men and 20 women) aged 38 to 65 years were studied. Subjects were randomly assigned to group A or B. Subjects in group A underwent biofeedback treatment once a week for a total of four sessions. Those in group B self-monitored their blood pressure during the sessions as the control period and later underwent the same biofeedback treatment. RESULTS: Blood pressure measured by doctor was reduced by 17 +/- 18/8 +/- 7 (p < .01) and elevation of pressure induced by mental stress testing was suppressed by 8 +/- 9 (p < .05)/4 +/- 8 during the treatment period in group A (mm Hg). In group B, both blood pressure measured by doctor and elevation of pressure by mental stress testing remained unchanged during the control period and they were later suppressed by 20 +/- 15/9 +/- 7 (p < .01) and 11 +/- 10(p < .05)/5 +/- 9 by the biofeedback treatment. Self-monitored pressure in both groups tended to decrease by the biofeedback treatment. Systolic and diastolic pressures as well as pulse rate decreased, skin temperature increased, and alpha-wave amplitude on electroencephalography increased during the therapy (p < .05). CONCLUSION: This treatment was effective in suppressing the pressor response to stress. Patients whose blood pressure increases with stress may be suited for biofeedback intervention.