tai chi

Tai chi is a form of exercise that combines deep breathing and relaxation with meditative, slow movements. Originally developed as a martial art in 13th-century China, tai chi is now practised around the world as a health-promoting exercise. Despite its popularity, its therapeutic value is not clear.

This randomized, assessor-blinded trial examined the therapeutic efficacy of tai chi for the management of central obesity. A total of 543 participants with central obesity were randomly assigned in a 1:1:1 ratio to:

  • a control group with no exercise intervention (n = 181),
  • conventional exercise consisting of aerobic exercise and strength training (EX group) (n = 181),
  • a tai chi group (TC group) (n = 181). Interventions lasted 12 weeks.

Outcomes were assessed at baseline, week 12, and week 38. The primary outcome was waist circumference (WC). Secondary outcomes were body weight; body mass index; high-density lipoprotein cholesterol (HDL-C), triglyceride, and fasting plasma glucose levels; blood pressure; and incidence of remission of central obesity.

The adjusted mean difference in WC from baseline to week 12 in the control group was 0.8 cm (95% CI, -4.1 to 5.7 cm). Both intervention groups showed reductions in WC relative to control (adjusted mean differences: TC group vs. control, -1.8 cm [CI, -2.3 to -1.4 cm]; P < 0.001; EX group vs. control: -1.3 cm [CI, -1.8 to -0.9 cm]; P < 0.001); both intervention groups also showed reductions in body weight (P < 0.05) and attenuation of the decrease in HDL-C level relative to the control group. The favorable changes in WC and body weight were maintained in both the TC and EX groups, whereas the beneficial effect on HDL-C was only maintained in the TC group at week 38.

The authors concluded that Tai chi is an effective approach to reduce WC in adults with central obesity aged 50 years or older.

This is a decent trial with an odd conclusion: it is not just the Tai chi intervention but both types of exercise that yield significantly positive effects on the primary outcome measure. So, why did the authors not conclude exercise is an effective approach to reduce WC in adults with central obesity aged 50 years or older?

Could it be that such a conclusion would have meant stating the obvious?

Traditional Chinese Medicine (TCM) is a term created by Mao lumping together various modalities in an attempt to pretend that healthcare in the People’s Republic of China (PRC) was being provided despite the most severe shortages of conventional doctors, drugs and facilities. Since then, TCM seems to have conquered the West, and, in the PRC, the supply of conventional medicine has hugely increased. Today therefore, TCM and conventional medicine peacefully co-exist side by side in the PRC on an equal footing.

At least this is what we are being told – but is it true?

I have visited the PRC twice. The first time, in 1980, I was the doctor of a university football team playing several games in the PRC, including one against their national team. The second time, in 1991, I co-chaired a scientific meeting in Shanghai. On both occasions, I was invited to visit TCM facilities and discuss with colleagues issues related to TCM in the PRC. All the official discussions were monitored by official ‘minders’, and therefore fee speech and an uninhibited exchange of ideas are not truly how I would describe them. Yet, on both visits, there were occasions when the ‘minders’ were absent and a more liberal discussion could ensue. Whenever this was the case, I did not at all get the impression that TCM and conventional medicine were peacefully co-existing. The impression that I did get was that their co-existence resembled more a ‘shot-gun marriage’.

During my time running the SCAM research unit at Exeter, I had the opportunity to welcome several visiting researchers from the PRC. This experience seemed to confirm my impression that TCM in the PRC was less than free. As an example, I might cite one acupuncture project I was once working on with a scientist from the PRC. When it was nearing its conclusion and I mentioned that we should now think about writing it up to publish the findings, my Chinese colleague said that being a co-author was unfortunately not an option. Knowing how important publications in Western journals are for researchers from the PRC, I was most surprised by this revelation. The reason, it turned out, was that our findings failed to be favourable for TCM. My friend explained that such a paper would not advance but hinder an academic career, once back in the PRC.

Suspecting that the notion of a peaceful co-existence of TCM and conventional medicine in the PRC was far from true, I have always been puzzled how the myth could survive for so many years. Now, finally, it seems to crumble. This is from a recent journalistic article entitled ‘Chinese Activists Protest the Use of Traditional Treatments – They Want Medical Science’ which states that thousands of science activists in the PRC protest that the state neglects its duty to treat its citizens with evidence-based medicine (here is the scientific article this is based on):

Over a number of years, Chinese researcher Qiaoyan Zhu, who has been affiliated with the University of Copenhagen’s Department of Communication, has collected data on the many thousand science activists in China through observations in Internet forums, on social media and during physical meetings. She has also interviewed hundreds of activists. Together with Professor Maja Horst, who has specialized in research communication, she has analyzed the many data on the activists and their protests in an article that has just been published in the journal Public Understanding of Science:

“The activists are better educated and wealthier than the average Chinese population, and a large majority of them keep up-to-date with scientific developments. The protests do not reflect a broad popular movement, but the activists make an impact with their communication at several different levels,” Maja Horst explained and added: “Many of them are protesting individually by writing directly to family, friends and colleagues who have been treated with – and in some cases taken ill from – Traditional Chinese Medicine. Some have also hung posters in hospitals and other official institutions to draw attention to the dangers of traditional treatments. But most of the activism takes place online, on social media and blogs.

Activists operating in a regime like the Chinese are obviously not given the same leeway as activists in an open democratic society — there are limits to what the authorities are willing to accept in the public sphere in particular. However, there is still ample opportunity to organize and plan actions online.

“In addition to smaller groups and individual activists that have profiles on social media, larger online groups are also being formed, in some cases gaining a high degree of visibility. The card game with 52 criticisms about Traditional Chinese Medicine that a group of activists produced in 37,000 copies and distributed to family, friends and local poker clubs is a good example. Poker is a highly popular pastime in rural China so the critical deck of cards is a creative way of reaching a large audience,” Maja Horst said.

Maja Horst and Qiaoyan Zhu have also found examples of more direct action methods, where local activist groups contact school authorities to complain that traditional Chinese medicine is part of the syllabus in schools. Or that activists help patients refuse treatment if they are offered treatment with Traditional Chinese Medicine.


I am relieved to see that, even in a system like the PRC, sound science and compelling evidence cannot be suppressed forever. It has taken a mighty long time, and the process may only be in its infancy. But there is hope – perhaps even hope that the TCM enthusiasts outside the PRC might realise that much of what came out of China has led them up the garden path!?


Alternative practitioners practise highly diverse therapies. They seem to have nothing in common – except perhaps that ALL of them are allegedly stimulating our self-healing powers (and except that most proponents are latently or openly against vaccinations). And it is through these self-healing powers that the treatments in question cure anything and become a true panacea. When questioned what these incredible powers really are, most practitioners would (somewhat vaguely) name the immune system as the responsible mechanism. With this post, I intend to provide a short summary of the evidence on this issue:

Acupuncture: no good evidence to show stimulation of self-healing powers.

Aromatherapy: no good evidence to show stimulation of self-healing powers.

Bioresonance: no good evidence to show stimulation of self-healing powers.

Chiropractic: no good evidence to show stimulation of self-healing powers.

Detox: no good evidence to show stimulation of self-healing powers.

Energy healing: no good evidence to show stimulation of self-healing powers.

Feldenkrais: no good evidence to show stimulation of self-healing powers.

Gua sha: no good evidence to show stimulation of self-healing powers.

Herbal medicine: no good evidence to show stimulation of self-healing powers.

Homeopathy: no good evidence to show stimulation of self-healing powers.

Macrobiotics: no good evidence to show stimulation of self-healing powers.

Naturopathy: no good evidence to show stimulation of self-healing powers.

Osteopathy: no good evidence to show stimulation of self-healing powers.

Power bands: no good evidence to show stimulation of self-healing powers.

Reiki: no good evidence to show stimulation of self-healing powers.

Reflexology: no good evidence to show stimulation of self-healing powers.

Shiatsu: no good evidence to show stimulation of self-healing powers.

Tai chi: no good evidence to show stimulation of self-healing powers.

TCM: no good evidence to show stimulation of self-healing powers.

Vibrational therapy: no good evidence to show stimulation of self-healing powers.

Vaccinations: very good evidence to show stimulation of self-healing powers.


As I have stated repeatedly, I am constantly on the look-out for positive news about alternative medicine. Usually, I find plenty – but when I scrutinise it, it tends to crumble in the type of misleading report that I often write about on this blog. Truly good research in alternative medicine is hard to find, and results that are based on rigorous science and show a positive finding are a bit like gold-dust.

But hold on, today I have something!

This systematic review was aimed at determining whether physical exercise is effective in improving cognitive function in the over 50s. The authors evaluated all randomised controlled trials of physical exercise interventions in community-dwelling adults older than 50 years with an outcome measure of cognitive function.

39 studies were included in the systematic review. Analysis of 333 dependent effect sizes from 36 studies showed that physical exercise improved cognitive function. Interventions of aerobic exercise, resistance training, multicomponent training and tai chi, all had significant point estimates. When exercise prescription was examined, a duration of 45–60 min per session and at least moderate intensity, were associated with benefits to cognition. The results of the meta-analysis were consistent and independent of the cognitive domain tested or the cognitive status of the participants.

The authors concluded that physical exercise improved cognitive function in the over 50s, regardless of the cognitive status of participants. To improve cognitive function, this meta-analysis provides clinicians with evidence to recommend that patients obtain both aerobic and resistance exercise of at least moderate intensity on as many days of the week as feasible, in line with current exercise guidelines.

But this is not alternative medicine, I hear you say.

You are right, mostly, it isn’t. There were a few RCTs of tai chi and yoga, but the majority was of conventional exercise. Moreover, most of these ‘alternative’ RCTs were less convincing than the conventional RCTs; here is one of the former category:

Community-dwelling older adults (N = 118; mean age = 62.0) were randomized to one of two groups: a Hatha yoga intervention or a stretching-strengthening control. Both groups participated in hour-long exercise classes 3×/week over the 8-week study period. All participants completed established tests of executive function including the task switching paradigm, n-back and running memory span at baseline and follow-up. Analysis of covariances showed significantly shorter reaction times on the mixed and repeat task switching trials (partial η(2) = .04, p < .05) for the Hatha yoga group. Higher accuracy was recorded on the single trials (partial η(2) = .05, p < .05), the 2-back condition of the n-back (partial η(2) = .08, p < .001), and partial recall scores (partial η(2) = .06, p < .01) of running span task.

I just wanted to be generous and felt the need to report a positive result. I guess, this just shows how devoid of rigorous research generating a positive finding alternative medicine really is.

Of course, there are many readers of this blog who are convinced that their pet therapy is supported by excellent evidence. For them, I have this challenge: if you think you have good evidence for an alternative therapy, show it to me (send it to me via the ‘contact’ option of this blog or post the link as a comment below). Please note that any evidence I would consider analysing in some detail (writing a full blog post about it) would need to be recent, peer-reviewed and rigorous.

In alternative medicine, good evidence is like gold dust and good evidence showing that alternative therapies are efficacious is even rarer. Therefore, I was delighted to come across a brand-new article from an institution that should stand for reliable information: the NIH, no less.

According to its authors, this new article “examines the clinical trial evidence for the efficacy and safety of several specific approaches—acupuncture, manipulation, massage therapy, relaxation techniques including meditation, selected natural product supplements (chondroitin, glucosamine, methylsulfonylmethane, S-adenosylmethionine), tai chi, and yoga—as used to manage chronic pain and related disability associated with back pain, fibromyalgia, osteoarthritis, neck pain, and severe headaches or migraines.”

The results of this huge undertaking are complex, of course, but in a nutshell they are at least partly positive for alternative medicine. Specifically, the authors state that “based on a preponderance of positive trials vs negative trials, current evidence suggests that the following complementary approaches may help some patients manage their painful health conditions: acupuncture and yoga for back pain; acupuncture and tai chi for OA of the knee; massage therapy for neck pain with adequate doses and for short-term benefit; and relaxation techniques for severe headaches and migraine. Weaker evidence suggests that massage therapy, SM, and osteopathic manipulation might also be of some benefit to those with back pain, and relaxation approaches and tai chi might help those with fibromyalgia.”

This is excellent news! Finally, we have data from an authoritative source showing that some alternative treatments can be recommended for common pain conditions.

Hold on, not so fast! Yes, the NIH is a most respectable organisation, but we must not blindly accept anything of importance just because it appears to come form a reputable source. Let’s look a bit closer at the actual evidence provided by the authors of this paper.

Reading the article carefully, it is impossible not to get troubled. Here are a few points that concern me most:

  • the safety of a therapy cannot be evaluated on the basis of data from RCTs (particularly as it has been shown repeatedly that trials of alternative therapies often fail to report adverse effects); much larger samples are needed for that; any statements about safety in the aims of the paper are therefore misplaced;
  • the authors talk about efficacy but seem to mean effectiveness;
  • the authors only included RCTs from the US which must result in a skewed and incomplete picture;
  • the article is from the National Center for Complementary and Integrative Health which is part of the NIH but which has been criticised repeatedly for being biased in favour of alternative medicine;
  • not all of the authors seem to be NIH staff, and I cannot find a declaration of conflicts of interest;
  • the discussion of the paper totally lacks any critical thinking;
  • there is no assessment of the quality of the trials included in this review.

My last point is by far the most important. A summary of this nature that fails to take into account the numerous limitations of the primary data is, I think, as good as worthless. As I know most of the RCTs included in the analyses, I predict that the overall picture generated by this review would have changed substantially, if the risks of bias in the primary studies had been accounted for.

Personally, I find it lamentable that such a potentially worthy exercise ended up employing such lousy methodology. Perhaps even more lamentable is the fact that the NIH (or one of its Centers) can descend that low; to mislead the public in this way borders on scientific misconduct and is, in my view, unethical and unacceptable.

Tai Chi has been suggested to have many health benefits. Might it even prolong life? There are many enthusiasts who claim just that, but is there any evidence?

This study is a retrospective cross-sectional investigation to compare the rejuvenating and anti-ageing effects among a Tai Chi group (TCC) and a brisk walking group (BW) and a no exercise habit group (NEH) of volunteers. Thirty-two participants were separated into three groups: the TCC group (practicing TC for more than 1 year), the BW group (practicing BW for more than 1 year), and the NEH group. The CD34+ cell counts in peripheral blood of the participants was determined, and the Kruskal‐Wallis test was used to evaluate and compare the antiaging effects of the three groups. The results show that the participants in the TCC group (N = 10) outperformed the NEH group (N = 12) with respect to the number of CD34+ progenitor cells. No significant difference was found between the TCC group and the BW group. The authors of this study conclude that TCC practice sustained for more than 1 year may be an intervention against aging as effective as BW in terms of its benefits on the improvement of CD34+ number.

I was alerted to this new paper by several rather sensational headlines in the daily press which stated that Tai chi (TC) had anti-aging effects. So I searched for the press release about the article where I found the following quotes:

“It is possible that Tai Chi may prompt vasodilation and increase blood flow,” said Lin. “Considering that BW may require a larger space or more equipment, Tai Chi seems to be an easier and more convenient choice of anti-aging exercise.” “This study provides the first step into providing scientific evidence for the possible health benefits of Tai Chi.” said Dr. Paul R. Sanberg, distinguished professor at the Center of Excellence for Aging and Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL. “Further study of how Tai Chi can elicit benefit in different populations and on different parameters of aging are necessary to determine its full impact.”

Personally, I find both the press release and the original conclusions of the authors quite amazing. If anyone wanted to write a textbook on how not to do such things, he/she could use them as excellent examples.

Seen with just a tinge of critical thinking the paper reports a flimsy case-control study comparing three obviously self-selected groups of people who had chosen to follow different exercise regimen for several months. In all likelihood they also differed in terms of life-style, nutrition, sleeping pattern, alcohol intake, smoking habits and a million other things. These rather tiny groups were then compared according to a surrogate measure for ageing and some differences were identified.


To conclude from this, or even to imply, that TC has anti-ageing effects is as far-fetched as claiming the tooth fairy has money problems.

This story could be just funny or trivial or boring – however, I think, it is also a bit worrying. It shows, I fear, how uncritical researchers in conjunction with some naïve press officer are able to induce silly journalists and headline-writers to mislead the public.

In China (and increasingly elsewhere too), the gentle, meditative exercise of tai chi is being promoted and used for disease prevention, particularly for the prevention of cardiovascular disease (CVD). But are these exercises effective? We carried out a Cochrane review to find out.

We searched both English language and Asian electronic databases as well as trial registers and reference lists for relevant studies. No language restrictions were applied. We considered randomised clinical trials (RCTs) of tai chi lasting at least three months and involving healthy adults or adults at high risk of CVD. The comparison groups received no or only minimal interventions. Our outcome measures were CVD clinical events and CVD risk factors. We excluded trials involving multifactorial lifestyle interventions or focusing on weight loss. Two reviewers independently selected trials for inclusion, abstracted the data and assessed the risk of bias of each included study.

We identified 13 trials with a total of 1520 participants and three on-going studies. All of them had at least one domain with unclear risk of bias, and some were at high risk of bias. Duration and style of tai chi differed between trials. Seven studies recruited 903 healthy participants, the other studies recruited people with hypertension, elderly people at high risk of falling, and people with ‘liver or kidney yin deficiency syndromes’.

No studies reported on cardiovascular mortality, all-cause mortality or non-fatal events as most studies were short-term. There was also considerable heterogeneity between studies, which meant that it was not possible to combine studies statistically for cardiovascular risk. Nine trials measured systolic blood pressure (SBP), and 6 of them found reductions in SBP. Two trials found no clear evidence of a difference, and one trial found an increase in SBP with tai chi. A similar pattern was seen for diastolic blood pressure (DBP): three trials found a reduction in DBP, while three found no clear evidence of a difference.

Three trials reported lipid levels and two found reductions in total cholesterol, LDL-C and triglycerides, while the third study found no clear evidence of a difference between groups on lipid levels. Quality of life was measured in only one trial: tai chi improved quality of life at three months. None of the included trials reported on adverse events, costs or occurrence of type 2 diabetes.

From these findings, we drew the following conclusions: “There are currently no long-term trials examining tai chi for the primary prevention of CVD. Due to the limited evidence available currently no conclusions can be drawn as to the effectiveness of tai chi on CVD risk factors. There was some suggestion of beneficial effects of tai chi on CVD risk factors but this was not consistent across all studies. There was considerable heterogeneity between the studies included in this review and studies were small and at some risk of bias. Results of the ongoing trials will add to the evidence base but additional longer-term, high-quality trials are needed.”

These findings are somewhat disappointing. Tai chi might convey many health benefits, but whether a reduction of cardiovascular risk is amongst them seems doubtful. Even if a risk reduction were established beyond doubt, one would need to ask whether its effect size is larger than that achievable through regular conventional exercise. In my view, this is unlikely.

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