Stress management and relaxation for hypertension

This systematic review/network meta-analysis assessed whether relaxation and stress management techniques are useful in reducing blood pressure in individuals with hypertension and prehypertension. The authors retrieved all studies published in English of adults with hypertension (blood pressure ≥140/90 mm Hg) or prehypertension (blood pressure ≥120/80 mm Hg but <140/90 mm Hg). Studies were considered that compared non- pharmacological interventions used to promote relaxation or reduce stress with each other, or with a control group (eg, no intervention, waiting list, or standard care). Studies were assessed with the risk of bias 2 tool (RoB2), and those at high risk of bias were excluded from the primary analysis. The certainty of the evidence was assessed with CINeMA (Confidence in Network Meta- Analysis).

A total of 182 studies were included (166 for hypertension and 16 for prehypertension). Results from a random effects network meta-analysis showed that, at short term follow- up (≤3 months), most relaxation interventions appeared to have a beneficial effect on systolic and diastolic blood pressure for individuals with hypertension. Between study heterogeneity was moderate (τ=2.62- 4.73). Compared with a passive comparator (ie, no intervention, waiting list, or usual care), moderate reductions in systolic blood pressure were found for breathing control (mean difference −6.65 mm Hg, 95% credible interval −10.39 to −2.93), meditation (mean difference −7.71 mm Hg, −14.07 to −1.29), meditative movement (including tai chi and yoga, mean difference −9.58 mm Hg, −12.95 to −6.17), mindfulness (mean difference −9.90 mm Hg, −16.44 to −3.53), music (mean difference −6.61 mm Hg, −11.62 to −1.56), progressive muscle relaxation (mean difference −7.46 mm Hg, −12.15 to −2.96), psychotherapy (mean difference −9.83 mm Hg, −16.24 to −3.43), and multicomponent interventions (mean difference −6.78 mm Hg, −11.59 to −1.99). Reductions were also seen in diastolic blood pressure. Few studies conducted follow-up for more than three months, but effects on blood pressure seemed to lessen over time. Limited data were available for prehypertension; only two studies compared short term follow- up of relaxation therapies with a passive comparator, and the effects on systolic blood pressure were small (mean difference −3.84 mm Hg, 95% credible interval −6.25 to −1.43 for meditative movement; mean difference −0.53 mm Hg, −2.03 to 0.97 for multicomponent intervention). The certainty of the evidence was considered to be very low based on the CINeMA framework, owing to the risk of bias in the primary studies, potential publication bias, and imprecision in the effect estimates.

The authors concluded that the results of our study indicated that many relaxation interventions show promise for reducing blood pressure in the short term but the longer term effects are unclear. Future studies in this area should include adequate follow-up to establish whether the effects on blood pressure persist over time, both while the relaxation interventions are ongoing and after they have been completed. Researchers should also use rigorous study methods and reporting to minimise the risk of bias in the results. Finally, we encourage researchers to assess all relevant outcomes, including cardiovascular events and adverse events, as well as blood pressure itself.

I was asked to provide a comment on this paper for a ‘Science Media Centre Roundup’ – here is what I wrote:

“This is a rigorous and important review. Its findings are eminently plausible: just like stress would increase blood pressure, so does relaxation decrease it. The problem, as I see it, might be compliance. Stressed people tend to be chronically pressed for time, and relaxation techniques take considerably more time than simply swallowing an antihypertensive pill.”