Relax, but is there rest for the blood pressure?

Abstract

Often patients report blood pressure values in the hypertensive range in response to excitement. A common statement is that the excitement (or stressful event) was enough to 'raise my blood pressure' or, in the clinic, an exciting period was the 'cause' of high blood pressure readings recorded on that day.Although no strong epidemiological evidence exists for an association between stress and sustained hypertension, clinicians and patients often seek relaxation therapy as an additional means to potentially lower blood in addition to behavioural and medical therapies. However, the definition of relaxation is often vague, and several techniques, including autogenic training, 1 behavioural therapy, 2 meditation, 2 biofeedback, 2 breathing exercises, 3 progressive muscle relaxation 4 or yoga 5 have been employed. So far, the effect of these different techniques to lower blood pressure has been assessed in relatively small clinical trials. Previous publications provided conflicting evidence, reviewed only a limited number of relaxation techniques or were restricted to studies covering only a short follow-up period. 1,[6][7][8] Given these limitations, Dickinson et al. 9 provided a refreshing and comprehensive systematic review of the available clinical trials of relaxation therapies for the management of primary hypertension in adults, which is published in the current issue of the Journal of Human Hypertension. They evaluated the effectiveness of relaxation to lower high blood pressure in their review and metaanalysed the available data. They searched the available literature for randomized controlled trials comparing relaxation therapies with no active treatment or sham therapy in patients with elevated blood pressure. In their meta-analysis they assessed the primary end points of death from all causes, coronary heart disease events, cerebrovascular events, systolic and diastolic blood pressure at the end of follow-up. They further aimed to compare the effectiveness of different relaxation techniques.Similarly to their previous review 10 assessing the effectiveness of lifestyle interventions for improvement of hypertension, they found only a weak causal association between relaxation and blood pressure reduction. Applying stringent criteria for the quality of trials, the vast majority of trials cannot be regarded as sufficient to address the posed question. Of around initially 2400 trials addressing the topic, only 25 trials assessing 1198 participants met the inclusion criteria for the meta-analysis. Only nine trials reported blinding of outcome assessors, adequate randomization was confirmed in only seven trials, and concealment of therapy in only one. The main finding of the authors, therefore, is the poor quality of the available trials. Even the trials that met the initial selection criteria had severe flaws. There was considerable heterogeneity between the single trials regarding number of patients, ethnicity, recruitment, type and combination of relaxation therapies, use of sham therapies, duration of follow...