Expectation and the blood-pressure-lowering effects of relaxation.

In a study of the blood-pressure-lowering effects of relaxation training in patients with essential hypertension, instructions concerning the relaxation procedure were varied so that one group was told to expect delayed blood-pressure-lowering and the other group immediate lowering. The systolic blood pressure decrease during the training period in the immediate lowering group was 17.0 mm Hg, compared with 2.4 mm Hg for the delayed group (p = 0.001). Diastolic blood pressure changes were not significantly different. Measures of therapy credibility and perceived relaxation failed to differentiate the groups. The implications of these findings for future research and for clinical practice are considered.