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Sue Shekut: Seeking feedback on massage research design

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March 24, 2012

Fellow POEM Members,

I am submitting my research design, “Massage Therapy Modality Effect on Blood Pressure, Cortisol and Anxiety“ to POEM for feedback from POEM members and suggestions on how to best operationally define the different modalities of massage therapy for research.

My goals in submitting this particular research design to POEM are:

  1. To give other massage therapists (MTs) a template for writing similar studies.
  2. To find like-minded MTs that may want to contribute to this study/elements of this study and perhaps do the actual research.
  3. To show other MTs that writing research designs is not that hard, can be done by an MT, and follows a standard format.
  4. To make sure that the work I put in thus far does not just sit in my computer gathering "dust".

 

The design isn't the best ever, but it addresses some of the issues we all face in design research for massage therapy.

 

My specific questions to fellow POEM members are as follows:

  1. Is the operational definition I include of deep tissue, Swedish and sports massage clear enough for others to replicate? Is it accurate?
  2. Does a specific protocol for each modality need to be defined for the study design?
  3. Does a specific protocol for each modality need to be defined for MTs that provide massage to ensure objective application of the modalities for each research subject?
  4. Are these three modalities the best representation of diverse types of massage for studying effects of BP, cortisol and anxiety? Would including other modalities or breaking down deep tissue into trigger point work and mysofascial release provide more useful data?
  5. Does the study need to operationally define “light, moderate and firm” pressure or is the subjective appraisal of pressure by MTs giving the massage of each level of pressure sufficient? If not, how best to operationally define pressure levels? Who defines pressure levels? The MTs, each research subject?

 

Note that I wrote the bulk of this design in 2010 and had not yet read Christopher Moyer's study on cortisol and massage. However, since Moyer’s study was not an experimental study, but a meta-analysis of previous research, I believe that further experimental research on the effects of massage on cortisol levels is warranted.

I welcome comments, feedback and offers of collaboration for this research project. Even if no one ends up conducting this particular research project, I hope that by reading and reviewing my work, other MTs may be empowered to conduct their own research and further the evidence base of the massage profession.

Warmly,
Sue Shekut, Licensed Massage Therapist
Graduate student in Clinical Professional Psychology at Roosevelt University

 


Massage Therapy Modality Effect on Blood Pressure, Cortisol and Anxiety
Susan J. Shekut
Roosevelt University
© 2012, Sue Shekut

Abstract

Stress management is an important issue in the workplace and for the individual. Massage therapy has been shown to reduce depression and anxiety as well as to reduce levels of cortisol and reduce blood pressure (BP). Massage modality can moderate the effect of onset of BP reduction and may moderate the effect of onset of cortisol reduction as well as self-reported anxiety levels. There are a number of types of massage, but for this study, only deep tissue, sports massage and Swedish massage styles were examined as to their effect on the blood pressure, cortisol and anxiety levels of 90 participants. It is expected that Swedish massage will decrease BP, cortisol and self reported anxiety to the greatest degree immediately following the massage intervention and that deep tissue and sports massage will have greater effects on BP, cortisol and anxiety reduction two days post massage intervention.

Massage Therapy Modality Effect on Blood Pressure, Cortisol and Anxiety

Workplace stress has recently been indicated to be one of the major causes of some of the costliest, most time-robbing health problems for business. According to the 17th World Congress on Health and Safety at Work, 13.4 million working days are lost due to stress, anxiety, and depression (17th World Congress on Health and Safety at Work).

Traditional approaches to stress management include psychological interventions such as cognitive behavioral therapy, mediation, diaphragmatic breathing and similar self-directed techniques (David & McKay, 2008). However, there is a growing trend among consumers to seek massage therapy as a form of stress relief. In a consumer survey published by the American Massage Therapy Association (AMTA) in 2009 found that 32 percent of Americans said they got a massage for stress and/or relaxation in the last five years.

Some believe the mechanism of effect for massage therapy may be primarily psychological (Moyer, Rounds, & Hammum, 2004). Others believe massage has a physiological effect as well. Studies show that massage therapy can be effective for anxiety and depression as well as a host of clinical conditions (Rich, 2010). Additionally, current research findings has shown that a single session of massage therapy reduces state anxiety, blood pressure and heart rate, and multiple sessions of massage reduce delayed onset of pain (Moyer, et al., 2004). Other studies show that participants’ salivary cortisol levels decreased following massage therapy (Field, et all, 1997). Yet none of these studies tested whether a specific massage therapy modality was responsible for producing these affects.

The Touch Research Institute of Miami University, a noted research facility in the field of massage therapy, has conducted a number of studies demonstrating the physiological effects of massage therapy. One of their studies found that healthy adults that received 15-minute chair massages twice per week for five weeks had marked improvement in EEG patterns of alertness and frontal delta power increases, which suggests relaxation (Field, et al., 1996). The massage recipients also showed increased speed and accuracy on math computations, lower anxiety levels, as well as lowered salivary cortisol levels on the first day of treatment. However, BP levels were not tested at all in this study–only anxiety and cortisol levels were tested.

Corporate companies have been using massage therapy as a reward and stress intervention for the past 10-15 years (reference). A 1996 (Shulman & Jones) quasi-experimental field study found significant reductions in anxiety levels for massage recipients as measured by the State-Trait Anxiety Inventory Self-Assessment Questionnaire. Researchers found that residual effects of the massage continued after cessation of the massage intervention and that there was a trend for stress levels to be more greatly reduced for those massage recipients that worked more than 40 hours per week and had higher education levels. However, they did not test the effect of the intervention on BP levels, cortisol levels or participants’ anxiety levels in this study.

Fifteen-minute chair massages on healthcare workers at a major hospital decreased job stress, anxiety and depression as well as decreased in urinary cortisol (Field, Quintino, Henteleff, Wells-Kief, & Delvecchio-Fienerg, 1997). However, chair massages can include a variety of massage modalities depending on the training of the massage therapists providing the massage intervention. Neither the massage modality was addressed nor was the massage intervention operationally defined in this study. Participant BP levels were not investigated either.

Field and her colleagues reviewed various massage studies and overall found that massage therapy decreases cortisol levels and increases urinary serotonin and dopamine levels (Field, Hernandez-Reif, & Diego, 2005). While Field and colleagues claim that the reduction in cortisol suggests that massage had stress-alleviating effects and that increases in urinary serotonin and dopamine suggest that they help reduce depression and the effects of stress, there is no significant relationship between serotonin and dopamine secreted in the urine and the amount of these neurotransmitters in the brain. Research has shown that neurotransmitters do not cross the blood brain barrier. According to a recent study published in the Journal of Urology, urinary serotonin and urinary dopamine do not show levels of serotonin and dopamine that were previously in the central or peripheral nervous system. Urinary serotonin and urinary dopamine are synthesized in the kidneys, not in the central nervous system (Hinz, Stein, Trachte, & Uncini, 2010). Therefore, measuring urinary levels of neurotransmitters is not a definitive test to measure depression or anxiety nor to test the effects of massage therapy on depression or anxiety. However, testing salivary cortisol is an accepted method of testing the changes in unbound cortisol in participants, due to the validity of salivary cortisol reflecting the level of cortisol in the blood and the relative ease with which salivary cortisol may be obtained from participants. Habitual smokers tend to show blunted cortisol responses to psychological stress and therefore should not be included in studies that measure cortisol changes in response to stress effecting interventions (Kirschbaum & Hellhammer, 1993).

Since blood pressure tends to increase with stress and the sympathetic nervous system response, measuring blood pressure changes has been one method researchers use to examine physiological effects of massage (Smith, T. W., Birmingham, W., & Uchino, 2012; Cambron, Dexheimer, & Coe, 2006). This would suggest that measurements of changes in BP may be a good physiological measurement of anxiety levels to assess effects of massage therapy. In a preliminary study, 150 adults with “normal” BP (under 150/95) were given different types of massages to determine the effect on blood pressure. Overall blood pressure decreased for massage recipients of all types of massages. However, those that received Swedish massages had the greatest effect on BP reduction. Trigger point and sports massage styles tended to increase systolic BP. If both sports and trigger point therapy massage were used in one session, then both diastolic and systolic BP increased. However, these results were not statistically significant. Blood pressure was measured using an automatic cuff which may have resulted in less accurate readings but the study authors were not concerned with measuring actual BP changes, but the overall effect of the massages on BP. Another potential threat to internal validity of this study was that the massage therapy students conducting the massages self reported the style of techniques they used. Additionally, the study was a case study and not powered for multiple statistical tests. Future researchers were recommended to use manual BP cuffs and provide for tighter controls on the type of massages used (Cambron, Dexheimer, & Coe, 2006).

Recent studies examined the effects of the level of pressure of massages given to participants to determine if light, moderate pressure, or vibratory massage would have a greater effect on parasympathetic nervous system activity (Diego, Field, Sanders, & Hernandez-Reif, 2004). Massage recipients felt less anxiety following massage sessions no matter what pressure
was used. However, those that received moderate pressure massages reported the greatest decreases in self-reported stress. The moderate massage group showed a significant decrease in heart rate during the massage, which continued into the post massage session.

Field and a colleague followed up this study with research on the effect of moderate pressure massage on EKG readings to determine if a parasympathetic response was the result of moderate pressure massage (Diego, Field, , Sanders, . & Hernandez-Reif, 2004). Results indicated that participants that received the moderate pressure, 15-minute massage showed an increase in high frequency ratio components of heart rate variability. This suggested an increase in parasympathetic nervous system activity. The study contended that the mechanism for action in increasing parasympathetic response was the stimulation of pressure receptors in the skin (Diego & Field, 2009). While yielding useful data as to the effects of the level of pressure, neither of these latter two studies measured BP levels, cortisol levels, or participant anxiety, only the heart rate variability of participants.

Despite the growing volume of research on massage therapy, none of these studies compare modality (type) of massage given to changes in cortisol levels, changes in BP levels or changes in perceived anxiety levels. Since previous studies show that BP increases with massage that produces more painful responses (trigger point therapy, sports massage and deep tissue), it is expected that cortisol levels, a measure of the stress response, will respond similarly to BP on the types of massage interventions. Since psychological stress has been shown to increase cortisol levels, it is expected that self reported anxiety levels will correlate with levels of BP and cortisol.

Swedish massage (which tends to be a more moderate pressure style of massage), deep tissue massage and sports massage tend to be deeper pressure massage modalities (AMTAWashington, 2010). Massage recipients typically report feeling the most relaxing effects of a deep tissue or sports massage a few days after the massage session as the initial effects may include soreness and fatigue. These results would be assessed post massage and then 2 days after the massage session.

Hypothesis 1: Blood pressure levels will be negatively correlated with Swedish massage therapy immediately following the intervention.

Hypothesis 2: Blood pressure levels will be negatively correlated with deep tissue and sports massage two days post intervention.

Hypothesis 3: Salivary cortisol levels will be negatively correlated with Swedish massage therapy immediately following the intervention.

Hypothesis 4: Salivary cortisol levels will be negatively correlated with deep tissue and sports massage two days post intervention.

Hypothesis 5: Self reported anxiety levels will be negatively correlated with Swedish massage therapy immediately following the intervention.

Hypothesis 6: Self reported anxiety levels will be negatively correlated with deep tissue and sports massage two days post intervention.

Method

Participants

The sample would include approximately 90 participants from an large city in the Midwest. They would be recruited from the area via fliers sent to area offices as well as at nearby retail stores. It would be expected that participants would be fairly well educated, both male and female of middle to upper middle socioeconomic status, and be representative of a variety of races and demographics of this area.

Participants would be ages 25-55, of normal health, no hypertension or heart disease (BP under 140/90–the threshold for indicating hypertension), be nonsmokers, not be pregnant and have no history of severe mental illness (e.g., depression, bipolar, schizophrenia). Participants would be screened to ensure that they had previously received massages and have had positive experiences with massage, but had not received massages for at least 6 months prior to the study. Participants would be randomly assigned to Swedish, Deep Tissue. and Sports massage groups. Participants would be blind to the type of massage they are being given. A short questionnaire would be included with their two-day follow up anxiety test to assess whether they knew the type of massage they were given. Participants would be instructed to avoid salty foods between the massage intervention and the two-day follow up. Incentive to return for their two-day follow up would be the receipt of a gift certificate for a 30-minute massage (modality of their choice) to be completed at a later date.

BP Testing Procedures

BP would be measured via a manual BP cuff 5 minutes prior to massage intervention and 5 minutes after the intervention. At two day follow up the BP will again be measured. Recordings of Diastolic and Systolic BP would be made for both pre and posttests. Changes in BP for each participant would be recorded.

Cortisol Testing Procedures

Salivary cortisol testing procedure would be conducted in the following order: Premassage session salivary samples would be taken 3 minutes prior to massage; Post massage, another salivary sample would be taken 3 minutes prior to massage; Two days after the massage intervention, a salivary sample would also be taken.

Anxiety Testing Procedures

The State-Trait Anxiety Inventory Form (STAI) will be used to measure anxiety in participants. The STAI clearly differentiates between the temporary condition of "state anxiety" and the more general and long-standing quality of "trait anxiety." (Spielberger, 1994). Participants will be given the STAI 10 minutes prior to the massage, 10 minutes after the
massage and two days after the massage.

Massage Interventions

Massages would be provided by three Licensed Massage Therapists with at least five years of full-time work experience in massage therapy and with advanced training in the types of massage they are to perform (Swedish, deep tissue and sports massage).

Massage therapists would be instructed to provide either a 30-minute session of Swedish massage on the upper torso, a 30 minute session of deep tissue massage on the back (including infraspinatus, rhomboids, trapezius, erector and quadratus lumborum muscles), or a 30-minute session post-event Sports massage session on the upper torso. Each massage therapist would provide a different type of massage to different participants to avoid experimenter bias from influencing results. Massages would be provided in the same room in the same office to hold environmental differences constant.

Types of massage will be operationally defined per the definition provided by Milady’s Theory and Practice of Therapeutic Massage as follows (Beck, 1994).

Deep tissue message. “The term deep tissue massage refers to various regimens or massage styles that are directed toward the deeper tissue structures of the muscle and fascia…In most deep tissue massage techniques the aim is to affect the various layers of fascia that support muscle tissues and loosen bonds between layers of connective tissues” (Beck, 1994, p. 548).

Sports massage. “Sports massage refers to a method of massage especially designed to prepare an athlete for an upcoming event and to aid in the body’s regenerative and restorative capacities following a rigorous workout or competition. This is achieved through specialized manipulations that stimulate circulation of the blood and lymph. Some sports massage movements are designed to break down lesions and adhesions or reduce fatigue” (Beck, 1994, p.16).

Swedish message. “The Swedish system is based on the Western concepts of anatomy and physiology and employs the traditional manipulative techniques of effleurage, petrissage, vibration, friction and tapotement” (Beck, 1994, p. 15). All three types of massage would be administered using moderate and not light pressure based on previous study findings that moderate pressure massage stimulates parasympathetic NS activity more so than light pressure massage.

Anticipated Results

Based on results of previous research noted in this study, it is expected that recipients of Swedish massage will have the greatest reduction in both BP and cortisol levels immediately following the massage. However, we also expect to find that BP and cortisol levels will be reduced more for the deep tissue and sports massage group than the Swedish massage group two days after receiving the massage intervention. It is expected that recipients of Swedish massage will report the least anxiety immediately posttest and that the recipients of deep tissue and sports massage will report the least anxiety two days post test. Results will be analyzed using one-way ANOVA tests.

References

AMTA-Washington chapter (2010) Retrieved from: http://www.amtawa.org/index.php?src=gendocs&ref=Modalities&category=Reso...

Beck, M. (1994). Milady's theory and practice of therapeutic massage. (2nd ed.). Albany: 1994 Milady Publishing Company.

Calvert, R. N. (2010) A Brief History of Massage. Retrieved from: http://www.massagetherapy.com/media/experiencehistory.php

Cambron, J. A., Dexheimer, J. & Coe, P. (2006) Changes in blood pressure after various forms of therapeutic massage: A preliminary study. The Journal of Alternative and Complimentary Medicine, 12(1), 65-70.

Davis, M., Eshelman, E., & McKay, M. (2008). The relaxation and stress reduction workbook (6th ed.). Oakland, CA US: New Harbinger Publications.

Diego, M. A., & Field, T. (2009) Moderate pressure massage elicits a parasympathetic nervous system response, International Journal of Neuroscience, 119, 630-638.

Diego, A., Field, T., Sanders, C. & Hernandez-Reif, M. (2004). Massage therapy of moderate and light pressure and vibrator effects on EEG and heart rate. International Journal of Neuroscience, 114, 31-45.

Field, T., Hernandez-Reif, (FI?) & Diego, M. (2005) Cortisol decreases and serotonin and dopamine increase following massage therapy. International Journal Neuroscience, 115, 1397-1413.

Field, T., Diego, M. & Hernandez-Reif, M. (2010) Moderate pressure is essential for massage therapy effects. International Journal of Neuroscience, 120, 381-385.

Field, T., Ironson, G., Scafidi, F., Nawrocki, T., Goncalves, A., Burman, I., Pickens, J., Fox, N., Schanberg, S., & Kuhn, C. (1996). Massage therapy reduces anxiety and enhances EEG pattern of alertness and math computations. International Journal of Neuroscience, 86, 197-205.

Field, Tiffany, Hernandez-Reif, M., Hart, S., Quintine, O., Droase, L. A., Field, T.,… & Schanberg, S. (1997) Effects of sexual abuse are lessened by massage therapy. Journal of Bodywork and Movement Therapies, 1(2), 65-69.

Field, T., Quintino, O., Henteleff, T., Wells-Kief L. & Delvecchio-Fienerg G. (1997). Job Stress reduction therapies. Alternative Therapies in Health and Medicine 3(4), 54-56.

Hinz, M., Stein, A., Trachte, G. & Uncini, T. (2010) Neurotransmitter testing of the urine, a comprehensive analysis. Journal of Urology, 2010(2), 177-183.

Kirschbaum, C. & Hellhammer, D., H. (1993) Salivary cortisol in psychoneuroendocrine research: Recent developments and applications. Psychoneuroendocrinology, 19(4), 313-333.

Kharrazian, D. (2009) Understanding the clinical relevance and non-validity of neurotransmitter testing. AlaimoChiropractic.com. Retrieved from: http://alaimochiropractic.com/urinaryneurotransmitter-testing-valid-or-h...

Moyer, C. A., Rounds, J, & Hannum, J. W. (2004). A meta-analysis of massage therapy research. Psychological Bulletin, 130(1). 3-18.

Ponce, A. N., Lorber, W., Paul, J. J., Esterlis, I., Barzvi, A., Allen, G. J., & Pescatello, L. S. (2008) Comparisons of varying dosages of relaxation in a corporate setting: Effects on stress reduction. International Journal of Stress Management 15(4), 396-407.

Rich, G. J. (2010). Massage therapy: Significance and relevance to professional practice. Professional Psychology: Research and Practice, 41(4). 325-332.

Schulman, K. R., & Jones, G. E. (1996) The effectiveness of massage therapy intervention on reducing anxiety in the workplace. Journal of Applied Behavioral Science, 32(2), 160-173.

Smith, T. W., Birmingham, W., & Uchino, B. N. (2012). Evaluative Threat and Ambulatory Blood Pressure: Cardiovascular Effects of Social Stress in Daily Experience. Health Psychology. Advance online publication. doi: 10.1037/a0026947

Spielberger, C. D., & Sydeman, S. J. (1994). State-Trait Anxiety Inventory and State-Trait Anger Expression Inventory. In M. Maruish, M. Maruish (Eds.) , The use of psychological testing for treatment planning and outcome assessment (pp. 292-321). Hillsdale, NJ England: Lawrence Erlbaum Associates, Inc.

Williams, A. (2005). Work-Related Stress Emerging as Major Global Occupational Health Hazard, National Safety Council press release. Retrieved from:http://www.nsc.org/Pages/Work-RelatedStressEmergingasMajorGlobalOccupationalHealthHazard.aspx

Arthritis Today magazine article about the benefits of massage for people living with arthritis

(h/t Bodhi Haraldsson for bringing this to my attention)

Interestingly, at the same time that the Journal Club is examining the effects of massage on cortisol, Arthritis Today just came out with an article on the benefits of massage therapy for people with arthritis, where the research on that claim is mentioned. You'll also see a couple of familiar names from Journal Club quoted in that article.

In the section titled "How Does Massage Work?" they repeat the claim that massage can lower cortisol levels:

 

While some studies show that massage can reduce pain and anxiety for people with arthritis, how exactly does massage make these results happen? Research has shown that massage can lower the body’s production of the stress hormone cortisol, and boost production of serotonin, which, in turn, can improve mood. Additionally, massage can lower production of the neurotransmitter substance P, often linked to pain, and improve sleep as a result.

 

They follow up with another study where the reduction in cortisol levels was not significant:

In 2010, researchers at the University of California, Los Angeles, School of Medicine and the nearby Cedars-Sinai Medical Center studied 53 healthy adults receiving just one Swedish massage therapy session and found that the participants’ levels of key hormones and white blood cells were positively affected. For example, the hormone arginine-vasopressin, which may lower blood pressure, was decreased, along with some inflammatory cytokines like IL-4 and IL-10. Cortisol levels were reduced by massage in this study as well, although not significantly.

 

and then they proceed to the research we're discussing in Journal Club.

Commenters Christopher Moyer (first author on the Journal Club research article) and rchunco (who is facilitating this month's Journal Club are quoted in the article. It's definitely worth a read.


I also find the claim about substance P interesting, and worth a follow-up. The Arthritis Today article doesn't mention the provenance (source) of the claim, stating only that:

massage can lower production of the neurotransmitter substance P, often linked to pain, and improve sleep as a result

 

To follow up, I did a PubMed search  on

massage AND "substance P"

and got 5 results, the following 2 of which bear relevance to the claim:

Abstract: Many animal species invest a large amount of time in grooming behavior without deriving any apparent benefit. In order for this behavior to have survived, however, it must confer some survival advantage. In seven of eight humans tested, an elevation in the skin's temperature was documented after massaging of the cheeks of the face. The elevation of the skin's temperature reached a plateau after about 40 min of massaging and was correlated to visible erythema. This effect could be inhibited by repeated pretreatment of the skin with topical capsaicin, a chemical that results in the release of substance P from peripheral nerve endings. Thus, it appears that the temperature elevation induced by stroking of human skin is controlled, at least in part, by release of the neurotransmitter, substance P. In conclusion, it appears that the release of neurotransmitter(s) may be the survival advantage that grooming confers to animals.
 
Abstract: Massage therapy has been observed to be helpful in some patients with fibromyalgia. This study was designed to examine the effects of massage therapy versus relaxation therapy on sleep, substance P, and pain in fibromyalgia patients. Twenty-four adult fibromyalgia patients were assigned randomly to a massage therapy or relaxation therapy group. They received 30-minute treatments twice weekly for 5 weeks. Both groups showed a decrease in anxiety and depressed mood immediately after the first and last therapy sessions. However, across the course of the study, only the massage therapy group reported an increase in the number of sleep hours and a decrease in their sleep movements. In addition, substance P levels decreased, and the patients' physicians assigned lower disease and pain ratings and rated fewer tender points in the massage therapy group.
 
Reading the abstracts instead of the articles is never safe; there are just too many errors in published articles and too much lack of detail to rely on the abstract to fairly represent the article enough to base an analysis on.
 
But I can read an abstract and decide on that basis whether it makes sense for me to go to the effort and expense of obtaining the entire article or not. 
 
The first one may be interesting, based on the abstract. I think they make quite a huge leap from the results of their study to the conclusion that grooming necessarily confers a survival advantage in animals, and that that survival advantage may lie in the release of neurotransmitters. However, the abstract itself is necessarily quite telegraphic, for reasons of space, and the article itself may do a better job of connecting those dots.
 
But the evolutionary biology claims aren't what we're interested in here. We're looking for the source of the claim that massage lowers levels of substance P, and there is enough information in the abstract of the article to determine the answer to that question.
 
Morhenn is claiming the following:
 
  • 40 minutes of firm massaging of the cheeks leads to

 

 

  • increased temperature [C] in the facial skin.

 

 

 

  • Topical capsaicin pretreatment inhibited massage from producing these results [D].

 

 

  • Therefore, the temperature elevation caused by massage involves--at least as part of the process if not the entire cause--release of the neurotransmitter substance P.

 

 

If, at this point, you're wondering whether you missed a step, no, it's not you. Morhenn is using one piece of knowledge implicitly--she is assuming that all her readers already have all the pieces--rather than stating it explicitly.

 

That piece of knowledge is that since capsaicin causes peripheral nerve endings to release the neurotransmitter substance P, and there is a lag time before they "recharge" with more substance P to release, that when the massage is taking place, there is temporarily no more substance P left for anything else to cause to release.

 

So her implicit (not fully spelled out) argument is that since massage causes increased temperature, etc. and that since this effect no longer occurs when capsaicin has caused the peripheral nerve endings to discharge their substance P, that the reason massage effects are blocked must be that massage produces its effects (at least, in part) through that very release of substance P. Since it's no longer there, due to the capsaicin, massage cannot produce the effects it normally would.

 

I can't tell from the abstract whether she's connected the dots thoroughly enough for a convincing interpretation--I'll have to look up the article later--but what I can tell is that this is not the source of the claim that massage reduces substance P.

 

In fact, Morhenn is claiming the opposite--that massage causes substance P to be released in this situation--so while I'll have a look later to see whether she connected the dots, both on this claim and on the larger evolutionary biology argument--I'll put it aside as a source for the claim in the Arthritis Today article.

 

That leaves only the Field article as the source of the claim, and indeed it is stated in the abstract. Since--as we're examining in Journal Club--her team used a weaker, non-standard methodology for the claims that massage lowered cortisol, I suspect the same may be true in their analysis of substance P levels.

 

I won't have a chance to get out to the medical library until this weekend, but when I do, I'll check it out, and report back on my findings.

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