Contributed by Derek R. Austin, PT, DPT, MS, BCTMB, CSCS, Renee Stenbjorn, BS, MPA, LMT, April Neufeld BS, LMP

If you did not already have enough reasons to get a stress-busting, mood-lifting, pain-relieving massage, this month's Massage Therapy Foundation research review details another great benefit of massage therapy. Promising research suggests that massage therapy can lower blood pressure. The study of the month explores the following questions: Is massage as effective as antihypertensive drugs to lower blood pressure? Does adding massage to antihypertensive drugs lower blood pressure further? The answer to these questions may be yes.

A rigorous analysis of research articles published on the topic of massage and hypertension was published in the Journal of Human Hypertension during 2014. Dr. Xing Jiang Xiong and his colleagues published the article with the title, "Massage therapy for essential hypertension: a systematic review." A systematic review aims to provide an exhaustive summary of current literature relevant to a research question. The question under study is how effective and safe is massage therapy for essential hypertension, meaning hypertension that has no known cause. The authors note that hypertension is the leading risk factor for mortality worldwide. Preliminary research has shown that complementary medicine approaches such as yoga, qigong, Tai Chi, acupuncture, and moxibustion may lower blood pressure. The researchers performed the first systematic review of randomized clinical trials to determine whether massage can combat hypertension.

The authors searched a large number of databases for randomized controlled trials published in English or Chinese. To be included, a study had to involve massage as an intervention for participants diagnosed with essential hypertension. The massage intervention had to be compared to a control group not receiving massage. Treatment duration of the analyzed studies ranged from a minimum of 10 days up to 1 year. Studies were excluded if the patients involved had a history of heart attack, kidney failure, liver failure, arrhythmia, or heart failure.

A total of 24 articles were selected and then analyzed for their risk of bias. The studies included a total of 1,962 patients with essential hypertension. Treatment groups included either massage alone or massage combined with antihypertensive drugs. Massage interventions were widely variable between studies, ranging from 1 hour per week to 45 minutes each day. Control groups received no intervention or antihypertensive drugs. Most studies were determined to be of generally poor methodological quality; for example, only 3 of the 24 studies included follow-up. The authors developed four categories of research, each compiled and analyzed using the process called meta-analysis. This statistical process comprises contrasting and combining results from different studies in the hope of identifying patterns among study results. Due to the statistical nature of this approach, only trials with quantitative data of blood pressure measurements could be included in the analysis.

The first group, of five studies, compared massage with no intervention. Only three of these studies provided blood pressure data in numerical terms. The researchers combined the results of these three trials and performed a meta-analysis to determine significance. The meta-analysis indicated no significant for massage in lowering blood pressure compared to no intervention.

The second group, of nine trials, compared massage to antihypertensive drugs, and six of these provided figures appropriate for meta-analysis. The meta-analysis showed that massage lowers systolic blood pressure better than antihypertensive drugs by an average of 3.5 mm Hg (p=0.0004). There was no significant effect on lowering diastolic blood pressure (p=0.14).

The third group, of eleven trials, compared antihypertensive drugs to massage combined with antihypertensive drugs, and six provided numerical values appropriate for meta-analysis. The meta-analysis indicated that massage plus antihypertensive drugs was superior compared to the antihypertensive drugs alone. Adding massage to antihypertensive drugs reduced systolic blood pressure by an average of 6.9 mm Hg (p=0.0001) and diastolic blood pressure by an average of 3.6 mm Hg (p=0.005). A meta-analysis of four of the other trials, which summarized the effect of massage based on grades of efficacy, also indicated that massage combined with antihypertensive drugs lowered blood pressure better than antihypertensive drugs alone (p=0.0002).

The final group, of five trials, reported adverse effects, and the authors' analysis showed that massage was potentially safer than antihypertensive drugs. While this conclusion is limited by the small number of trials reporting adverse events, massage may provide an effective alternative for those who suffer serious side effects from antihypertensive drugs.

The authors conclude that combining massage with antihypertensive drugs may be more effective than using just antihypertensive drugs to lower blood pressure. They also conclude that massage alone appears beneficial for reducing systolic blood pressure when compared with antihypertensive drugs.

One of the main strengths of this article is the thoroughness of its search for research articles and its inclusion of research articles published in either Chinese or English. Including Chinese language articles greatly expanded the number of articles included in the review, as massage is frequently studied in China. Other strengths include the rigorous assessment of methodological quality and the use of meta-analysis to combine published research data.

The authors report that the primary weakness of their review is the poor quality of the original studies. They note that many of the included trials did not report randomization procedures, concealment of allocated groups, whether individuals dropped out, pre-trial estimation of sample size. The most important weakness of the included studies was the lack of follow-up; it remains unclear whether massage would continue to have any effects on blood pressure beyond the end of the treatment period.

Due to the wide use and acceptance of massage therapy in general, massage could be an important adjunct therapy for treating hypertension in the primary care setting. Further research can help determine exactly how effective massage is in lowering blood pressure. A cost-efficacy analysis would also be useful, since essential hypertension is tremendously common, and yet many effective antihypertensive drugs are quite expensive. Future research will also help determine the most effective dose of massage and how massage interacts with different classes of antihypertensive drugs.

Not sure you understand the difference between a confidence interval, p-value, t-test, and ANOVA? MTF offers a course on the Basics of Research Literacy that teaches massage therapists and educators how to incorporate principles of research literacy into your practice and teaching. In this online, 8-hour, NCBTMB-approved workshop, you will be introduced to basic research vocabulary and concepts. Once you understand the terminology, you will learn how to use databases to look up research, evaluate the validity of published research articles, and apply research findings to improve massage outcomes. Your massage therapy practice can be improved by becoming more research literate.

To learn more about the effects of massage therapy, you can review the Massage Therapy Foundation review article archives, read accepted MTF Research Grant abstracts, or search PubMed for massage therapy studies.

Reference:

• Citation: Xiong XJ, Li SJ, Zhang YQ. Massage therapy for essential hypertension: a systematic review. J Hum Hypertens. 2015 Mar;29(3):143-51. doi: 10.1038/jhh.2014.52. Epub 2014 Jul 3. Review. PubMed PMID: 24990417.