Massage has long been seen as a way for people to decrease their stress levels. With the growing number of people seeking massage therapy care in recent years, it becomes increasingly important to understand if it is effective in managing the negative health consequences of stress. In this month’s article review, we explore work from a team of experienced researchers who provided a review of the existing literature in this area.
Albert Moraska, Robin Pollini, Karen Boulanger, Marissa Brooks, and Lesley Teitlebaum in their 2008 article, “Physiological Adjustments to Stress Following Massage Therapy: A Review of the Literature,” provided a critical evaluation of peer-reviewed research that had investigated the relationship between massage therapy and physiological measures of stress. The authors emphasized that reviews like this one are important to understanding the effectiveness of massage therapy in the management of the health impacts of stress.
In this literature review, massage therapy was defined as “the manipulation of soft tissues for the purpose of producing physiological effects on the vascular, muscular or nervous systems of the body.” Only studies where massage therapy was applied within the context of this definition were included, so any studies involving light touch modalities were excluded. The research group only included studies where the massage was provided by trained therapists and those with adults as the participants. This process of deciding what studies will be included and excluded is called setting the inclusion criteria.
With these criteria in mind, the research team conducted a broad and extensive search of several electronic research databases, along with the researchers’ own libraries, for articles that pertained to “stress” in combination with “massage,” “bodywork,” “physiotherapy,” and “manual therapy.” Articles were included when “presenting dependent variables of stress that included the hormones cortisol, epinephrine, norepinephrine, or physical measures of blood pressure (BP) and heart rate.” Of the initial 1032 citations reviewed that met the search parameters, only “25 articles were found to meet all inclusion criteria.”
The research team found that the 25 studies employed a diversity of experimental methods. There was large variability in session duration, “from 5 to 90 minutes, with over half (52%) of the studies having a session duration between 20 and 30 minutes.” Commonly, 6 to 10 treatments were delivered, but data was most often collected following the first session. The researchers chose not to report on specific massage techniques used as the specific techniques used were reported in varying degrees of detail and those studies had varied results.
“Study populations were varied and included sexually abused women, patients with eating disorders, pain conditions, hypertension, HIV positive diagnosis, cancer, post-operative patients, critical care patients, healthy adult populations, and some specific disease states.” Hormones that are markers for stress response were also noted by the researchers in this review.
Salivary cortisol is easy to collect from the mouth and non-invasive, so massage therapy studies frequently use this method for assessing cortisol levels. Of those studies that measured reductions in salivary cortisol, it appears that the decrease, although significant, maybe short term. There does not appear to be a cumulative reduction in salivary cortisol levels with multiple massage treatments. The subject populations in these studies were highly varied, “which suggests that many groups may experience an immediate benefit from massage therapy for this variable…However, most study participants were either healthy adults or experiencing chronic life stress.”
Urinary cortisol has been used to assess changes following multiple massage treatments. The studies that assessed urinary cortisol did so at baseline and after 5 weeks of twice-weekly massage and found evidence of a cumulative reduction in urinary cortisol.
“Epinephrine (adrenaline) is produced mainly from the adrenal medulla and reflects the subject’s sympatho-medullar activity” [activity from this gland]. “Epinephrine output is mainly influenced by mental stress.”
“Norepinephrine (noradrenaline) is considered an indicator of sympatho-neuronal [sympathetic nervous system] activity as most of the circulating norepinephrine is released from sympathetic nerve endings. This hormonal defense reaction is aimed at routing energy from organs to muscles for the muscles” and “is more responsive to physical activity” than to mental stress. However, the authors state a decrease in either of these hormones “may indicate a physiological reduction in stress” routing circulation from organs to muscles.
Cardiovascular responses reported in 16 of the studies were blood pressure and heart rate. “Increases in blood pressure, respiration, and heart rate are all physiological manifestations of the sympathetic nervous system’s response to stressful events.” There were mixed results in the studies reporting these responses, with the differences including what body parts were massaged, the massage techniques applied, the overall health of the study participants, duration of the massage session, and single-session versus multiple sessions. No studies reported an increase in blood pressure. Also, the effect of massage on heart rate, although not sustainable, seemed to be repeatable as decreases the following massage occurred one visit after the next.
It was noted by the research team that their review was based on the outlined inclusion criteria. The authors contrasted their review with a meta-analysis completed by Moyer et al. (2004). The results of the two reviews were not consistent. The two reports differed with respect to levels of salivary cortisol and blood pressure; the Moyer et al. (2004) report found no massage sessions that affected salivary cortisol and did find a change for blood pressure. The authors of the current review conclude that the difference in findings reveals more about the current state of massage therapy research than about the clinical effects of massage therapy on stress measures. Overall, “the studies reviewed showed a variety of methodological shortcomings.”
Of significant interest to readers is the authors’ conclusion that “to date, the research on massage therapy and stress has not progressed to demonstrate efficacy in a trial of sufficient size or methodological rigor to make definitive statements about its efficacy in reducing stress as measured by physiological variables in any particular patient population.” It is unfortunate that the evidence does not support making strong conclusions about the impact of massage therapy on physiological stress indicators. It is also unclear why there is no mention of heart rate and blood pressure in the keywords listed as search criteria in the current review, even though these non-hormonal markers of stress were included in the review. This may lead to difficulty in having this review come up in other literature searches.
The authors identify opportunities for future studies to examine the effectiveness of massage therapy. Based on the diversity among the studies in the current review, the authors emphasized the need for research that employs methodological rigor including large sample sizes, detailed and reproducible treatment protocols, and reporting of clinical and statistical significance.
The Massage Therapy Foundation continues to support and promote research as seen in this month’s review. The Foundation is currently accepting scientific submissions for our 2016 International Massage Therapy Research Conference (IMTRC) that will be held in Seattle, Washington, May 12-15. More information about the conference as well as the submission guidelines are now available on our website at www.massagetherapyfoundation.org.