Effect of a biofeedback system using an auto-shaping method on blood pressure at rest and during stress in mild hypertension

There is still controversy over whether biofeedback is efficacious in the treatment of hypertension. This study investigated the effect of a short period of biofeedback treatment using an auto-shaping method on clinic blood pressure (BP), self-measured BP and BP reactivity to psychosocial stress. Twenty-four outpatients with untreated stage 1 essential hypertension aged 20 to 55 years were enrolled. Subjects were randomly assigned to group A or B. The two groups were well balanced for age, sex, body mass, and BP level. Subjects in group A underwent biofeedback treatment using an auto-shaping method with a personal computer once a week for a total of four sessions and self-monitored their BP throughout the treatment period and for two weeks after the end of treatment. Those in group B did not receive biofeedback treatment and self-monitored their BP for six weeks. All subjects underwent continuous Finapres BP monitoring at baseline and after four weeks. During the recordings, the following two tests were performed: 1) BP measurement by a doctor unknown to the subject (white-coat reaction), and 2) 4 sets of speech test with different content in front of an audience (simulated public speaking). Clinic BP was reduced by 11/10 mmHg during treatment in group A whereas it remained unchanged in group B (p .018/ .001). Also self-monitored BP decreased in group A and not in group B (p .001/ .014). The white-coat reaction was attenuated in subjects of group A compared to subjects of group B (p .017/.024). Also the BP response to laboratory-modeled public speaking with anxiety content was smaller after treatment in subjects of group A than in those of group B though the difference did not attain the level of statistical significance. A short period of biofeedback treatment proved effective in reducing BP measured either in the clinic or outside the hospital environment. Furthermore, biofeedback was able to smooth the BP response to stress. Biofeedback appears to be a suitable intervention for hypertensive patients chiefly for those whose BP increases with stress.