Originally published in Massage Bodywork magazine, February/March 2007. Copyright 2007. Associated Bodywork and Massage Professionals. All rights reserved.
Massage therapy helps to decrease blood pressure, right? Not necessarily. It may depend on the type of massage applied, according to researchers at the National University of Health Sciences in Lombard, Illinois. In a study published in the Journal of Alternative and Complementary Medicine
(2006), Jerrilyn Cambron, DC, and her team report the effects on blood pressure change for six types of massage administered to a group of one hundred fifty normotensive and prehypertensive adults. What they found is that the potentially painful techniques of trigger point and sports massage were associated with an increase in systolic blood pressure, and when the two techniques were combined in a session, there was a significant increase in both diastolic and systolic readings.
Noting the conflicting results of previous research on the effect of massage on blood pressure, the team set out to determine if the type, duration, or force of massage, or certain patient characteristics, are associated with blood pressure change. The importance of this type of research is reflected in the high incidence of hypertension in our society. Approximately thirty percent of the population are reported to have this condition1
and although prescribed drugs are readily available, not all patients can or choose to go this treatment route. If studies can tweak out the specific factors and effects of massage associated with blood pressure change, there may be potential for this nonpharmacologic approach to serve as an effective alternative.2Identifying Factors of Change
The massage interventions utilized in this study included Swedish, deep tissue, myofascial release, sports, trigger point, and craniosacral. Treatment sessions, administered by twenty-five massage students in the second and third trimester of training, varied from thirty to ninety minutes in duration. Students were trained to provide massage based on client need, thus the integration of types of massage for each session also varied and did not follow a specific study protocol. After their treatment session, each student completed a survey detailing the type(s) of massage provided, amount of pressure used, body areas massaged, and duration of session.3
The subject group was recruited from returning clients at the university's massage therapy clinic. It was anticipated that new clients may evidence an increase in blood pressure due to apprehension rather than a physiologic factor associated with the massage, thus they were excluded. An initial blood pressure reading was taken prior to massage, with the students using an automated cuff for measurement. Authors point out the cuff is less accurate than manual methods, but they were not concerned with an exact blood pressure reading itself, but rather the changes documented following massage.4
For each type of massage integrated in a session, data was recorded for that individual application. Because more than one type was used in any single session, the data used to assess effect on blood pressure change reflect the total number of times any single type of massage was administered. With this approach, the team was also able to extract information related to the effect on both systolic and diastolic blood pressure when more than one type was combined.5
The majority of subjects received some Swedish massage and although it appeared there was a decrease in systolic blood pressure associated with this type, the result was not statistically significant. With deep tissue, myofascial, and craniosacral, no significant effect was noted in either direction of blood pressure change. The most significant findings were for trigger point and sports massage, with both showing an increase in systolic blood pressure following massage, more notably for trigger point. Both diastolic and systolic readings significantly increased when these two types were combined. The team suggests trigger point and sports massage may induce a pain response, with an accompanying increase in sympathetic nerve activity and blood pressure increase.6
But what about deep tissue, another potentially painful approach? In addressing this issue, Cambron says, "Increase in blood pressure occurs with the pain response, so perhaps if trigger point therapy and/or sports massage were painful, the blood pressure responsively increased. I expected the blood pressure to also increase with deep-tissue massage. However, it seems that many students have not yet developed a sense of how deep the deep-tissue massage should be and tend to err on the side of being conservative (lighter pressure rather than heavy). We may find much different results in experienced therapists."
Another of the treatment factors assessed--that of amount of pressure used during massage--showed no association with blood pressure change.7
Considering the fact that amount of pressure was individually determined by the students in their self-report--essentially, the students' perceptions--and not through an established protocol guideline, it would seem these results may be in question. "We did a follow-up study to assess this very issue," Cambron says. "Using a pressure transducer on a massage table, we asked the students to demonstrate their light, medium, and heavy massage pressures, and collected the information into the computer.
"We found that all students were able to incrementally increase their pressure from light to heavy. However, what some students considered light pressure, other students considered heavy pressure.
In other words, there was no consistency of light, medium, or heavy pressure between the students. However, the main problem with this study was that the students were asked to exert their sample pressures statically over the pressure transducer sitting on the massage table, rather than dynamically demonstrating the different pressure gradients on a human body." Cambron says the results were not submitted for publication because of potential bias, but it's a subject that deserves further exploration. "In the near future, we plan to continue looking into the issue of the inter- and intra-therapist consistency of light, medium, and heavy pressure during massage, particularly in experienced therapists rather than in students."
The team also assessed data on body areas massaged, duration of each session, and the level of training for massage students (second or third trimester), but none of these factors showed an association with blood pressure change. When it came to baseline characteristics of the subjects, there were some notable differences. Overall, the group showed an average decrease in systolic blood pressure and a negligible average increase in diastolic pressure. Participants ranged from age nineteen to seventy-nine years old (average about forty-two years), and it was the younger subjects who demonstrated significantly greater changes in systolic pressure. Height also factored in, with those of taller stature showing more significant change. Other characteristics (gender, race, usage of blood pressure medication, and weight) were of no significant effect, but the authors write, "There did appear to be a trend of decreased pressure readings in males, Hispanics, and heavier individuals."8
However, in regard to these characteristics, participants were primarily female (about sixty-one percent) and white (about eighty-nine percent), and most were not on blood pressure medication (eighty-eight percent).9A Useful Framework
The information gained in this study provides a useful framework for future research. A major strength of the study is the large sample size, and in their report Cambron et al. note the few other studies in this area have been small. Hernandez-Reif et al. (2004) compared massage to muscle relaxation in a sample size of thirty subjects with hypertension. The results did show a more significant decrease in systolic and diastolic readings for massage as compared to the control, but the experimental intervention was a single massage type formatted for the study.10
Similar results come from another small study (Ciney, 2005) with fourteen subjects clinically diagnosed with hypertension, in which a ten-minute massage was compared to an equal period of relaxation. Massage again effected a significant decrease in both systolic and diastolic readings.11
Although Cambron's team is the first to assess specific characteristics of massage that may affect blood pressure, they point out this study had its own limitations. As noted previously, the independent data were gleaned from the students' subjective self-report. The automated cuff, while sufficient to measure change, was not calibrated for validity, and use of a manual reading would be preferable in the future. The issue of a potential pain response with trigger point and sports massage increasing blood pressure is one that needs further exploration. The team cites a study by Delaney et al. (2002) in which trigger point therapy effected a decrease in blood pressure of healthy subjects. However, they point out the massage provided to the subjects included a type of stroking that may have stimulated the carotid sinus and caused the reduction in blood pressure. "Future studies on blood pressure changes in massage may include a survey question on pain felt during the massage in order to determine if this is the factor associated with blood pressure increase," the team writes.12The Take-Home Message
As with many studies, at the conclusion we have as many questions as answers, and that's a good thing. What we learn leads to further exploration. "Larger studies are needed in which the treatment groups are better defined with only one form of massage per group and with more seasoned massage therapists performing the therapy," Cambron says. With the increasing incidence of hypertension as our population ages, this will be an important area of work. Chances are one-third of a therapist's clients may walk in with hypertension, whether the therapist is aware of it or not. While the therapist may think her massage will attenuate the problem, it could have the opposite effect. "The main take-home message of this study," Cambron says, "is that different forms of massage have different effects on clients' bodies. Therefore, therapists need to be aware of each client's response during and after massage.
"Massage affects the body in many different ways, and we are not yet aware of all the physiological changes that occur," Cambron says. "Massage research is at a very exciting point, with investigators making frequent new discoveries." Cambron is an enthusiastic researcher and no doubt will continue to contribute to our knowledge. But she has one more take-home message for therapists working daily in the field.
"Massage therapists are gaining momentum in the area of research, and therapists are educating themselves on how to read and understand the research literature," Cambron says. "One area of research in which all therapists can be involved is case reports. A case report or case study is an informational discussion of a client who had an unusual presentation to the therapist or who had an amazing outcome due to the massage provided. Case reports are one of the best ways for the therapists in the field to share new information with other healthcare providers, and these reports allow researchers to know what is happening out in the field so we can move forward with larger studies." Notes
1. CDC National Center for Disease Statistics, "Hypertension." www.cdc.gov/nchs/fastats/hyprtens.htm (accessed November 2006).
2. J. A. Cambron, J. Dexheimer, and P. Coe, "Changes in blood pressure after various forms of therapeutic massage: a preliminary study," Journal of Alternative and Complementary Medicine 12, no. 1 (Jan-Feb 2006): 66.
3. Ibid., 66-67.
5. Ibid., 69.
6. Ibid., 68-69.
7. Ibid., 68.
9. Ibid., 67.
10. Ibid., 66.
11. C.M. Olney, "The effect of therapeutic back massage in hypertensive persons: a preliminary
study," Biological Research for Nursing 7, no. 2 (2005): 98-105.
12. Cambron, 69.