Voluntary blood pressure control by biofeedback: relationship to psychological characteristics

1. Psychological characteristics were studied in 25 hypertensives (mean and standard deviation of blood pressure 150/95 ± 12/5 mmHg), who received blood pressure (BP) biofeedback (BFB). Personality factors and success in BFB–BP modifying ability were correlated and the predictive value of psychological factors was estimated. 2. Questionnaires consisted of a Locus of Control of Behaviour (LCB) scale, the Spielberger state trait anxiety inventory and the Framingham Type A personality inventory. 3. BP was monitored continuously from the finger by volume clamp plethysmography during eight BFB sessions, each with three trials of raising, ignoring and lowering systolic blood pressure (SP). 4. SP was raised/lowered by 12 ± 11/6 ± 9 mmHg and heart rate (HR) increased by 10 ± 3.9/+ 1 ± 6.1. Ten subjects were able to lower SP by ≥5 mmHg (15 ± 7.5) and raise it by 17 ± 11. The others achieved no decrease in SP and were also less successful at raising (8 mmHg, P= 0.04). 5. Changes in LCB and trait anxiety correlated with DP rise, whereas type A and pre‐study state anxiety correlated with rising HR. Lowering of SP correlated weakly with change in LCB (r= 0.47, P= 0.06). 6. Combinations of psychological factors had independent predictive value for BP and HR change: trait anxiety (P= 0.03) and change in LCB (P= 0.009) with rise in diastolic blood pressure (DP); type A (P= 0.009), pre‐study LCB (P= 0.02) and pre‐study state anxiety (P= 0.01) with HR rise. 7. These findings suggest that psychological factors correlate with BP and HR changes during attempted BFB control of SP. The best predictor for a rise in DP was change in LCB.