Research Commentary  September 2018
Sep 3, 2018
This is the third review in a four-part series on complementary and alternative healthcare in New Zealand focussing on Yoga.
Yoga is a widely recognised form of exercise practiced by millions of people world-wide. This commentary focuses on the evidence for the purported health benefits. In this review meditation and yoga are shown to be scientifically effective alternative therapies for decreasing blood pressure in a systematic review (Park & Han, 2017). Yoga is a low-impact, slow-moving, and easily modifiable activity that makes it a suitable exercise for low-risk pregnant women. The study by Babbar et al. (2016), shows that yoga has benefits for pregnant women with no adverse effects on the fetus. The study by Yadav et al. (2017) indicates that even a short-term yoga-based intervention was effective in reducing CVD risk in subjects at low to moderately high risk. Yoga is an accepted therapy for chronic low back pain (Saper et al., 2017).
Commentary provided by Dr Annette Mortensen, eCALD® Services Project Manager: Research and Development
The following articles are reviewed:
Article 1: Framingham Risk Score and Estimated 10-Year Cardiovascular Disease Risk Reduction by a Short-Term Yoga-Based Lifestyle Intervention.
This Indian study evaluated the efficacy of a short-term yoga-based lifestyle intervention in reducing cardiovascular risk in terms of the Framingham Risk Score (FRS) and estimated 10-year CVD risk in subjects at low to moderate risk for CVD. The study demonstrated that even a short-term yoga-based intervention was effective in reducing CVD risk in subjects at low to moderately high risk. The Framingham risk scoring system is one of the best methods to determine CVD risk and to predict the cumulative 10-year CVD risk.
The yoga-based lifestyle intervention programme administered to the participants in the study was an outpatient, regular, ongoing programme. The programme comprises theory and practice sessions under the direct supervision of yoga and medical experts for about 2 hours each day for 10 days, spread over 2 weeks. The programme includes: a set of stretching exercises; asanas (physical postures) in standing, sitting, prone, and supine positions; pranayama (breathing exercises); meditation; and shavasana (a relaxing technique) for 1 hour. This is usually followed by lectures/group discussions regarding stress management, diet, and disease-specific lifestyle measures. The benefits of the long-term effect of this yoga-based lifestyle were explained to the participants, and they were encouraged to include the changes into their lifestyle to sustain these benefits. For those with a particular interest the asanas and pranayama exercises included in the intervention, are detailed in the study.
In the study, there was a 15% reduction in FRS following a 2-week yoga-based lifestyle intervention, which was statistically significant. There was an 11% reduction in estimated 10-year risk following this short-term yoga-based lifestyle intervention, which was also statistically significant. In line with the reduction in FRS and estimated 10-year CVD risk, there was a significant reduction in most of the individual cardiovascular risk factors (eg smoking, poor diet, and physical inactivity), suggesting the positive impact of the yoga-based lifestyle intervention on these parameters.
An important finding of this study was a significant reduction in FRS in both male and female participants, while the reduction in estimated 10-year risk was significant in males only. This could be due to the fact that males had a higher CVD risk at baseline.
Importantly, the study largely included subjects with a low CVD risk who could be potential candidates for lifestyle intervention alone in order to prevent or delay the progression of CVD later in life. On the other hand, subjects with intermediate to high CVD risk would be potential candidates for pharmacotherapy in combination with a lifestyle intervention. The main limitation of this study was the non-randomised, single-arm, historical cohort design, and the lack of a control group, which needs to be addressed in future studies in order to substantiate the benefits of a yoga-based lifestyle intervention on CVD risk in the long term. In addition, only the short-term benefits were observed in this study, and the results need to be validated in a long-term study. Nonetheless, it is apparent that the benefits are evident as early as 2 weeks, and such a lifestyle modification in the long term is promising.
Authors: Yadav, R., Yadav, R.K., Sarvottam, K. & Netam, R.
Citation: Yadav, R., Yadav, R.K., Sarvottam, K. & Netam, R. (2017). Framingham Risk Score and Estimated 10-Year Cardiovascular Disease Risk Reduction by a Short-Term Yoga-Based Lifestyle Intervention. The Journal of Alternative and Complementary Medicine, 23 (9), 730–737
Article 2: Blood Pressure Response to Meditation and Yoga: A Systematic Review and Meta-Analysis.
The primary goal of this study was to use systematic research to provide a scientific basis for the effectiveness of meditation and yoga in the management of typical hypertension patients based on RCT results. The study also attempted to suggest concrete evidence using meta-analysis. Interestingly, the 13 selected studies revealed that meditation and yoga have been researched more actively in the United States and Canada than in Asia, although meditation and yoga have been increasingly used globally as alternative medicines for hypertension.
The meta-analysis incorporated a total of seven studies on the use of meditation to treat hypertension, and the results presented evidence that meditation can have a systemically significant effect in decreasing both systolic (mean difference:-7.37mmHg) and diastolic (mean difference: -5.43mmHg) BP.
The effect of yoga for reducing BP was integrated by six studies. Although the conclusions for yoga indicated lower effectiveness compared with meditation in reducing BP (SBP: -4.59mmHg; DBP: -3.65mmHg), the results did confirm an effect on BP reduction that was similar to that found with meditation. Yoga can reduce BP, and these results showed stability without heterogeneity, especially in participants below the age of 60. Yoga was associated with a less significant decrease than was meditation, particularly regarding SBP in subjects older than 60 years of age. Subgroup analysis revealed that different ages and BP levels of subjects are the cause of heterogeneity among studies.
Authors: Park, S-H, & Han, K.S.
Citation: Park, S-H, & Han, K.S. (2017). Blood Pressure Response to Meditation and Yoga: A Systematic Review and Meta-Analysis. The Journal of Alternative and Complementary Medicine, 23 (9), 685-695.
Article 3: Yoga, Physical Therapy, or Education for Chronic Low Back Pain: A Randomized Non-inferiority Trial.
Compared with previous trials of yoga for chronic lower back pain (cLBP), this American trial enrolled more ethnically diverse, lower SES population participants. Mostly low-income, ethnically diverse adults with nonspecific chronic lower back pain (n=320) were randomised to participate in weekly yoga classes for 12 weeks, attend 15 physical therapy sessions or receive an educational book and newsletters in this non-inferiority trial. The aim of the study was to determine if yoga was at least as effective as current physiotherapy management of chronic lower back pain.
During a maintenance phase, yoga drop-in classes and physical therapy booster sessions were compared with home practice. Compared with physical therapy, Roland Morris Disability Questionnaire and pain scores obtained from the yoga group met the criterion for non-inferiority, but yoga was not superior to education for either outcome. Most of the secondary outcomes assessed (pain medication use, global improvement, satisfaction and health-related quality of life) were similar in the yoga and physical therapy groups, and participants from these respective groups were 21 and 22 percentage points less likely to use pain medication at 12 weeks than those in the education group. Improvements among yoga and physical therapy recipients persisted at 1 year with no between-group difference.
Not surprisingly, both the intervention groups suffered from a lack of adherence, which likely accounts for absence of group effects but the greater numbers of individual responders in the yoga and physiotherapy groups. It was also noteworthy that booster sessions made no difference to outcomes, which conflicts with other studies, but may also have been impacted by the lack of attendance at the booster classes.
The authors attribute the modest effect of yoga and PT in their trial compared to other studies (Sherman et al., 2011), to lower compliance with the exercise interventions offered, in part due to the obstacles facing lower SES populations (transport, conflicting life demands such as work, child care, and elder care etc). Another reason for the modest effect of the interventions may be the severity of the participants' back conditions compared to other studies. Baseline mean back-related disability and pain scores were 63% and 57% more severe, respectively, in our study than in Sherman and colleagues' (2011) study. Opioid use, obesity, depression, and other comorbid conditions were also more common.
Citation: Sherman, K.J., Cherkin, D.C., Wellman, R.D., Cook, A.J., Hawkes, R.J., Delaney, K., et al. (2011). A randomized trial comparing yoga, stretching, and a self-care book for chronic low back pain. Arch Intern Med, 171, 2019-26. [PMID: 22025101] doi:10.1001/archinternmed.2011.524.
Authors: Saper, R.B. Lemaster, C., Delitto, A. et al.
Citation: Saper, R.B. Lemaster, C., Delitto, A. et al., (2017). Yoga, Physical Therapy, or Education for Chronic Low Back Pain: A Randomized Noninferiority Trial. Annals of Internal Medicine, 167 (2), 85-94.
Article 4: Acute fetal behavioral response to prenatal yoga: A single, blinded, randomized controlled trial (TRY yoga).
The Ministry of Health ‘Being active during pregnancy guidelines’ encourage pregnant women to have 30 minutes of daily exercise (moderate intensity) on most days throughout the course of the pregnancy. This study supports the view that yoga can be considered a form of exercise for low-risk women which would meet these recommendations.
In this American study, the authors conducted a single-blinded randomised prospective trial comparing a yoga sequence with the control intervention. A total of 46 patients (mean age, 25 years; 31 weeks gestational age) were randomised. The yoga intervention was delivered by a certified yoga instructor who had specialised training in prenatal yoga. It consisted of a one-time class involving 23 postures, 1 breathing technique, and an 8 to 10-min final resting pose. This was accompanied with educational materials to perform this at home. The control intervention received education based on the American Congress of Obstetricians and Gynecologists (ACOG) guidelines.
Outcomes were reported at baseline and immediately after the intervention. The primary outcome was fetal wellbeing, as assessed by umbilical artery Doppler indices (systolic to diastolic ratio, resistance index, and pulsatility index), fetal heart rate, and biophysical profiles. No significant change in metrics of fetal well-being was found in the intervention group, as compared with the control, including findings in fetal blood flow or fetal behaviour. Of note, the study found that both groups had increases in their report of exercising by participating in this study. This suggests that a simple reiteration of exercise in pregnancy guidelines can result in improved compliance with recommendations.
This study is unique in that it utilised a fetal outcome as the primary outcome. Although the study was limited by this being a one-time intervention, this is consistent with other prenatal studies. If yoga caused any type of fetal hypoxia or distress, it would have persisted in the time frame of the post-intervention Doppler studies. Helpfully the article includes the yoga sequences used in this study.
Citation: Ministry of Health (2017). Being active during pregnancy. Wellington: Ministry of Health.
Authors: Babbar, S., Hill, J.B., Williams, K.B., et al.
Citation: Babbar, S., Hill, J.B., Williams, K.B., et al. (2016). Acute fetal behavioral response to prenatal yoga: A single, blinded, randomized controlled trial (TRY yoga). Am J Obstet Gynecol, 214, 399.e1–e8.