Blogging on Peer-Reviewed ResearchIf you ever want to wonder why I’m sometimes of the mind that the National Center for Complementary and Alternative Medicine should be disbanded and its functions distributed among the other Institutes of the NIH, you just have to consider the sorts of woo-filled studies (like the Gonzalez protocol) funded by NCCAM mixed in among the more reasonable studies of herbal remedies and other modalities that have at least a modicum of scientific plausibility. With that in mind, I came across a study that seems to be getting a fair amount of play in the press, at least around here. The study purports to demonstrate that Tai Chi boosts the immunity to varicella zoster, the virus that causes shingles, in the elderly. Sounds great, right? Unfortunately, that’s not exactly what it really appeared to show. You’ll see what I mean, but first the abstract:

OBJECTIVES: To evaluate the effects of a behavioral intervention, Tai Chi, on resting and vaccine-stimulated levels of cell-mediated immunity (CMI) to varicella zoster virus (VZV) and on health functioning in older adults.

DESIGN: A prospective, randomized, controlled trial with allocation to two arms (Tai Chi and health education) for 25 weeks. After 16 weeks of intervention, subjects were vaccinated with VARIVAX, the live attenuated Oka/Merck VZV vaccine licensed to prevent varicella.

SETTING: Two urban U.S. communities between 2001 and 2005.

PARTICIPANTS: A total of 112 healthy older adults aged 59 to 86.

MEASUREMENTS: The primary endpoint was a quantitative measure of VZV-CMI. Secondary outcomes were scores on the Medical Outcomes Study 36-item Short-Form Health Survey (SF-36).

RESULTS: The Tai Chi group showed higher levels of VZV-CMI than the health education group (P<.05), with a significant rate of increase (P<.001) that was nearly twice that found in the health education group. Tai Chi alone induced an increase in VZV-CMI that was comparable in magnitude with that induced by varicella vaccine, and the two were additive; Tai Chi, together with vaccine, produced a substantially higher level of VZV-CMI than vaccine alone. The Tai Chi group also showed significant improvements in SF-36 scores for physical functioning, bodily pain, vitality, and mental health (P<.05). CONCLUSION: Tai Chi augments resting levels of VZV-specific CMI and boosts VZV-CMI of the varicella vaccine.


So just doing Tai Chi for 16 weeks boosts immunity to varicella, apparently, if this study is to be believed.My first thought in seeing this study was to wonder why on earth the investigators came up with the hypothesis that (1) Tai Chi might boost immunity to varicella zoster and (2) that it would improve response to the vaccination. Did they see old people doing Tai Chi not getting shingles as often? Are they using immunity to varicella as a convenient marker for general immunity? Did they just pull the hypothesis out of their behinds? Inquiring minds want to know! And where on earth did they get the idea to give VZ vaccine at the end of the study period? True, they mentioned how immunity and response to vaccines in general are not as robust in the elderly and that they were looking for ways to boost immunity

So let’s look at this study. I’ll give the investigators props for at least randomizing their studies. That makes it better than at least 90% of “alternative medicine” studies out there. Heck, that makes it better than probably 99% of alternative medicine studies out there. But randomization alone does not make a good study. Equally important is what the experimental groups are and what the control is. So what, exactly, are the experimental groups, both of which are only briefly mentioned in the abstract. Let’s take a look at the Methods section of the paper (note: TCC=Tai Chi; HE=health education):

Subjects received 16 weeks of TCC or HE administered to groups of seven to 10 persons. TCC sessions lasted 40 minutes and were given three times per week for a total 120 minutes of weekly instruction. HE was also allocated a 120- minute period of instruction per week, an identical amount of instructor time as given to TCC. The rationale communicated to subjects was that TCC is a health management intervention that incorporates meditation and repetitive physical activity to promote well-being in aging, whereas HE aims to promote healthy behaviors and well-being by providing knowledge about health management. For TCC, objectives and learning activities related to the specific set of 20 exercises employed were identified according to a therapist manual,29 with verification of skills attainment and weekly supervision by master’s level TCC instructors. The HE intervention involved 16 didactic presentations on a series of health-related themes provided by a physician or licensed clinical psychologists with group discussion, as previously described.30 Treatment credibility and expectation were assessed for change after the second treatment session using a 5-point Likert scale.

Now do you see the problem?

Let me submit to you that I believe that the results are probably valid, even though the subjects were not blinded. For one thing, blinding the subjects of a study like this to the experimental group is virtually impossible anyway; so this is probably the best design that can be done. I believe that Tai Chi in this study actually did modestly boost the measures of immunity studied and the response to the VZV. But that is not the same thing as believing that Tai Chi has any special properties. What I submit to you is that what was really being studied here were two groups, one of which underwent regular, mild exercise (Tai Chi), and the other of which basically sat on their behinds in a class for the same period of time. In other words, the result is not at all surprising. After all, there is a fair amount of literature to suggest that exercise improves immune function in the elderly. Tai chi is nothing more than an exercise regimen, with some meditation thrown in. Why wouldn’t it have similar effects? If the investigators really wanted to see if Tai Chi had any special properties, at least two more control groups would be needed. One of these could be a group that did mild exercise, like walking, to the same estimated level as the Tai Chi regimen. The other could be a “sham” Tai Chi group, in which the participants were told that they were doing Tai Chi but were being led in the “wrong” moves. Heck, if they really wanted to get fancy, they could have separated the meditation and exercise components of Tai Chi and study them.

Maybe I’m just in a bad mood. Maybe I’m just too cynical. Maybe I’m being too harsh on this study, but the whole thing irritates me. My guess is that, had this been a simple study of mild exercise and immunity in the elderly, it wouldn’t have gotten nearly the play that it did. Heck, I’m not even sure it would have been funded in these days of extremely tight NIH dollars. Moreover, contrary to some of the blogospheric commentary, this study most assuredly did not show that Tai Chi prevents shingles; no differences in the incidence of shingles or severity of attacks was studied, and, as the authors pointed out, the increase in antibody response does not correlate reliably with immunity to shingles. But Tai Chi is popular and associated with “alternative” medicine. It’s also associated with woo:

Zhang Gao, a Chinese Kung Fu 6th Duan master who is the 2006 USA National Champion winning four Gold medals and one Silver medal, told that among other things Tai Chi helps the flow of vital energy called Qi, which is believed to be responsible for health benefits. Mr. Gao used Qi to effectively treat patients with colds, stomachache, headache, high blood pressure and other illnesses in China. Gao now runs a martial art school in St. Louis teaching a variety of Chinese Kung Fu styles including Tai Chi and Qi Gong.

Of course, whatever benefits Tai Chi has or does not have, they are not due to alterations in qi or any other “vital energies.” They’re almost certainly due to the duller and more prosaic explanation that it’s physical activity. Of course, I’m guessing that it’s because of the woo that Tai Chi gets studied because it’s a “sexier” subject, when in fact it’s pretty likely that any mild-to-moderate exercise would have produced the same results.


  1. #1 MR
    April 12, 2007

    Can I do a corollary study on the health effects of Chai Tea? I think it would yield some delicious conclusions.

    On a relevant note, I agree about it being physical rather than “subtle” or “vital” (ie. magical) effects, but it is still good to get people excercising. If people want to believe in chakras or energy that isn’t defined as the ability to do work, I call em silly. But, if that silliness gets them off the couch and doing yoga or tai chi or just good ole jogging, then at least some good has come of it.

  2. #2 daedalus2u
    April 12, 2007

    It is the placebo effect, which happens to be mediated by increasing nitric oxide. Most of the positive effects of exercise are also mediated by increased NO but generated through physical exercise rather than by mental effects. The nocebo effect (I will harm) is mediated by decreased nitric oxide. Depending on what condition is being “treated”, either a placebo or a nocebo can make it “better”. But by far more conditions are helped by increasing NO than by decreasing it. I am working on a blog to cover it. I hope to have it done this weekend, so stay tuned.

    Meditation does increase NO, which is responsible for most of they physiological effects of meditation, which incidently, are virtually identical to what the placebo effect does, although most research on placebos is related to pain rather than other effects.

  3. #3 Robert M.
    April 12, 2007

    I don’t think you’re being overly cynical; my first thought on reading the abstracts was the same as yours. Tai chi is mild, low-impact exercise, combined with meditation. “Exercise is healthy” isn’t exactly a revolutionary concept, and meditation is a lot like prayer–or petting your cat, for that matter; it has physiological effects like lowering blood pressure, assisting slightly with oxygen intake, and decreasing levels of stress hormones.

    Two hours of any mild exercise, followed by cooldown periods involving controlled deep breathing and any relaxation technique, likely would have yielded the same effect.

    It’s immensely frustrating to see people invoke the supernatural, rather than Occam’s razor and their own common sense. I can only imagine PZ’s take on a study like this.

  4. #4 Theodore Price
    April 12, 2007

    I read the paper, they have an R01 from National Inst of Ageing and an R21 from NCCAM. I agree with your take but I would just point out that the authors did not invoke the supernatural (from Robert M’s comment). The only thing they really say is that Tai Chi is unique for the combination of exercise and relaxation technique (sounds like yoga). I’m inclined to agree that it doesn’t make me too happy to see R01 money going to stuff like this but getting people off their butts (especially as they get older) is important and if studies such as these can get them to do it then great. I suppose; however, that it will have no effect on that whatsoever and its main result will be quotes for ads for Tai Chi centers to rip people off.

  5. #5 Ahistoricality
    April 12, 2007

    How does stuff with holes this big — I’m no scientist, but I saw it coming — get funded and, more to the point, published?

    Really, I’d like to know, because I’ve got all kinds of half-assed ideas which have never seen print, and won’t because my field has a pretty high threshold of review (and no funding to speak of…)

  6. #6 factician
    April 12, 2007


    It’s particularly depressing that this crap gets funded, given how brutal funding at the NIH is getting. For young investigators (like myself) who are considering academic careers, it’s a very difficult time to get funded. How much of a difference would it make to dissolve the NCCAM and fold that into real research? Maybe not a lot, but it would still be money better spent.


  7. #7 Athena
    April 12, 2007

    I was surprised to find this gem in the NIA press release:

    Both groups showed significant declines in the severity of depressive symptoms.

    It makes me wonder if the investigators enrolled subjects with clinical depression or they measured improvement in a condition with which subjects weren’t diagnosed.

    No reported improvement in baldness thankfully.

  8. #8 James Taylor
    April 12, 2007

    TaiChiJuan is great exercise. It will strengthen your core and legs substantially. It takes discipline to continue the daily routine of practicing basics, but it is a wonderful form of physical exercise that you can safely do into your golden years. It will keep you in peek condition. However, we never really discussed Chi. I took WuShu, what a MeiGuoRen(American) calls KungFu, as well and both are just exercises. WuShu is the hard art and TaiChi is the soft art. Mysticism comes from any obsession. People ascribe too much to what they do not understand and actors desire fame and fortune. My LaoShi(Masters) were genuine and they laugh at the bunk that comes attached to TaiChi and WuShu.

  9. #9 James Taylor
    April 12, 2007

    And you get to use a sword. 😉

  10. #10 Orac
    April 12, 2007

    Oh, I have no doubt that Tai Chi is fine low impact exercise. The point that perhaps I didn’t make as well as I might have is that, if this had just been a study about mild exercise and immunity in the elderly, it probably wouldn’t have been funded and it certainly wouldn’t have gotten as much attention. But add the “alternative” angle to it, and suddenly it’s news.

  11. #11 James Taylor
    April 12, 2007

    It is roughly the equivalent of funding a study on the health benefits of tap dancing.

  12. #12 epador
    April 13, 2007

    Thank you, MR. I was about to make a post about spice-addled and bovinated Assam, but you’ve relieved me of that duty. That stuff is guaranteed to get more than your Qi moving.

  13. #13 bcpmoon
    April 13, 2007

    I have to remind me not to assume higher brain functions in CAM-Practitioners. When I read “Health Education” in the abstract, I naturally assumed that this actually involved doing exercises, not learning about them. In fact, there was no control group at all. Pathetic.

  14. #14 Calli Arcale
    April 13, 2007

    “It is roughly the equivalent of funding a study on the health benefits of tap dancing.”

    I seem to recall reading of a study on the health benefits of ballroom dancing, so that’s close. I don’t recall the details, but it showed pretty much what you’d expect — getting off your butt and doing some aerobic exercise is good for you. That one lacked the “alternative medicine” angle, but it got reported because of the current fashion for ballroom dancing as a sport.

  15. #15 Flying Fox
    April 13, 2007

    I’ve noticed that in marital arts chi (or qi in the pinyin system, ki in Japanese) seems to refer to several different things. In aikido and kenjutsu, my martial arts of choice, chi seems to include force, momentum, body language, oxygen in your lungs, volume of voice (in kiai, the art of martial shouting) etc.

  16. #16 Flying Fox
    April 13, 2007

    I want to add mental state or “mind over matter” to my list of things chi covers. Its fun to learn how much your mental state has to do with things like balance.

  17. #17 guthrie
    April 13, 2007

    My first thought on reading the first few paragraphs was to wonder whether they had tested any other kinds of mild exercise for the same properties.

  18. #18 James Taylor
    April 13, 2007

    Flying Fox, Chi is the same in the Chinese Arts, except for the shouting part unless it is Southern Style. Just like when westerners first witnessed WuShu demonstrations in China and asked “What is that” and they were told “technique/skill” (KungFu), the westerners believed that because it was what they were told and took away the belief that Chinese arts are called KungFu. I think someone once asked “How do you do that” and the response was “Chi” and the myth was born out of the oversimplified description of hard work, practice, control, balance, power and discipline. It then became elevated to a mystical woo because most people don’t have the capacity for what it really takes.

  19. #19 trrll
    April 13, 2007

    I guess that I don’t quite see the point. Did the paper claim that there was anything magical about Tai Chi? On its face, it is an exercise that is well suited to the elderly in its physical demands, and that many people find enjoyable enough to do on a regular basis. So if I were seeking a physical exercise regimen to test for efficacy in improving immune function in the elderly, Tai Chi would be my first choice.

  20. #20 trrll
    April 13, 2007

    Chi seems to have originally meant “breath,” an to be derived from a pneumatic theory of physiology in which the breath circulates throughout the body in physical channels. Given that nobody has ever found such channels, and circulation of breath is limited to the lungs (maybe somebody got the idea from dissecting birds?), those who continue to believe in the literality of chi imagine it to be some kind of ineffable, unmeasurable energy.

    In the martial arts, the term has come to be used very flexibly, even by those who do not regard it as a physical “energy.” It is frequently used to refer to the less physically apparent aspects of technique–subtleties like mindset, intent, direction of intention, balance of muscular relaxation and tension, breathing, etc.

  21. #21 James Taylor
    April 13, 2007

    The language barrier is substantial within China itself and it is a very credulous society. The broad culture has only modernized in the last fifty years and the standardization of the language only occurred within that time frame as well. If you were to go from village to village today and knew how to speak Manderin, you would find that you still cannot communicate with ninety percent of the population as every village has its own distinct dialect and very few are educated. Hell, in China it is considered unhealthy to swallow your own saliva. Myths grow out of ignorance, not enlightenment. The myth of Chi grew out of this incubator of incoherent communication and magical thinking.

  22. #22 daedalus2u
    April 15, 2007

    I have posted a blog about the placebo effect, hoping to dispell some of the myths.

    I link to a paper where they measured increased immune response to vaccination due to meditation using antibody titers.

    The beneficial effects of exercise are not due to the exercise per se, rather they are due to the increased repair of cellular systems that follows exercise. There are multiple ways to invoke these repair systems. That is one thing that effective placebos do. They simply turn on the normal physiological repair systems that are already there.

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