Yoga Medical News Daily

Review of research studies on yoga and its health benefits

This research studies review by Alyson Ross, M.S.N., R.N., and Sue Thomas, F.A.A.N., Ph.D., R.N., of the School of Nursing, University of Maryland, Baltimore, MD., compared the effects of yoga and exercise on a variety of health outcomes and conditions. The authors used 81 studies that met their criteria and found that "yoga interventions appeared to be equal or superior to exercise in nearly every outcome measured except those involving physical fitness." 

The studies reviewed documented previous research that showed yoga is equal or superior to exercise in relieving certain symptoms associated with diabetes, multiple sclerosis, menopause, kidney disease, and schizophrenia. And as with exercise, yoga has been found to benefit blood glucose levels in individuals with diabetes. In addition, yoga has been shown to be effective in relieving symptoms of depression, anxiety, obsessive–compulsive disorder, and schizophrenia. 

The review concluded that "in both healthy and diseased populations, yoga may be as effective as or better than exercise at improving a variety of health-related outcome measures." Abstract: PubMed.  Article: "The Health Benefits of Yoga and Exercise: A Review of Comparison Studies," Journal of Alternative and Complementary Medicine [2010 Jan;16(1):3-12]. Photo by The U.S.Army.

Research trends during 2009 - yoga up 10.7%, pilates up 36%, tai chi down 45%

Taking a look at the number of documents added to the PubMed database, it is evident that 2009 saw a dramatic increase in medical research publications focusing on the health benefits of yoga and pilates.

Yoga Research Statistics for 2009:  A search in PubMed showed that during 2009 a total of 134 new documents mentioning yoga were added to that database, an increase of 10.7% from the 121 added in 2008. Looking back 10 years, there were just 31 documents mentioning yoga added to PubMed in 1999.

The total number of publications listed in PubMed relating to "yoga," was as of the last day of 2009: 1.341. Using GoPubMed, a search of "yoga" on December 31, 2009, revealed that the top countries producing yoga research and submitting research documents to the Pubmed database over a span of many years were the United States (346) and India (208). Specific cities producing the most yoga research findings of the total listed in the PubMed database: Bangalore was tops with 81 publications, followed by New Delhi (34) and New York (29), in second and third place. The most frequent contributor of articles relating to yoga, of the 1,341 in the PubMed database, is S. Telles with 53, followed by H. Nagendra, with 33.

Pilates Research Statistics for 2009:  The number of medical studies added to PubMed in 2009 that mention pilates - just 15. Compared to the 11 articles published in 2008, this represents a 36% increase in medical research publications relating to pilates. And the 15 articles published in 2009 are considerable, given the fact that there are only a total of 45 documents in the entire PubMed database mentioning pilates.

Tai chi Research Statistics for 2009:  During 2009 there were a total of 53 documents mentioning tai chi added to the PubMed database. This represents a 45% decline from the 97 documents relating to tai chi added in 2008 to PubMed. There are a total of 452 documents in the PubMed database that mention tai chi.

YMN Daily editorial comment:  A statistical/informal take on these 2009 research numbers as well as the focus of many of the studies published during the past year may suggest that research is moving gradually towards a closer look at the health benefits of more intense, sustained exercise interventions for all healthy age groups and some conditions. 

Yoga medical research: past, present, future

  There are now several articles that describe the status of research done on the medical benefits of yoga. One of the most comprehensive is by S.B. Khalsa ["Yoga as a therapeutic intervention: a bibliometric analysis of published research studies," Indian Journal of Physiology and Pharmacology (2004 Jul;48(3):269-85) Abstract: PubMed. Fulltext: Journal Archives. ] who points out that ". . .  for the time period 1973 to 1989, the number of Indian and U.S. published RCT's [randomized controlled trials] was 11 and 2, respectively. From 1990 to 2004 the number of Indian-based studies was 21, a two-fold increase, whereas the number of U.S. studies was 16, an eight-fold increase." Focusing on a select number of studies and looking forward from a public health perspective, Laci Scott in "Yoga off the mat: How far and to whom do the benefits extend?" (M.P.H. thesis, The University of Texas School of Public Health, 2008 Abstract], suggests that "Future research should seek to increase sample size, to diversify recruitment to allow for the randomization of treatment and control groups, and to allow for long-term follow-up." 

Another study that deals less with the medical details and more with historical aspects is Elizabeth De  
Michelis's very perceptive, richly documented overview "A Preliminary survey of modern yoga studies," Asian Medicine (2007; 3, issue 1:1-19). De Michelis points out that "The 'medicalisation' of yoga, and its dialogue with science, started in the 1920's in India . . . ." and carries her discussion forward to the present.

What might future yoga medical research ideally encompass? There are many variables - funding being the most obvious. But the trajectory for more comprehensive, focused yoga medical studies is already evident. YMN Daily suggests a likely scenario for future yoga research done in the U.S.: (1) longer-term clinical trials involving larger randomized treatment and control groups; (2) greater "customization" of research approaches to fit the condition (already seen in studies relating to diabetes and osteoporosis); and likewise (3) more "customization" of treatment. More subtle gradations are now appearing that focus on specific approaches (Iyengar, Ashtanga) or asanas.