By Nikhil Ramburn and Sat Bir Singh Khalsa, Ph.D.
Back pain is characterized by muscular pain, which may also include shooting pain that radiates down the legs and limited flexibility or range of motion of the back and neck. Because of the wide spectrum of symptoms, back pain may receive a variety of diagnoses such as sciatica or herniated disks. The nondescript form that lacks a precise diagnosis is called Low Back Pain (LBP). LBP is one of the leading causes of absence from work and is a major public health concern in industrialized societies. The condition is widely prevalent with up to 85% of individuals experiencing at least some degree of back pain in their lifetime. Although 90% of all patients with acute LBP recover rapidly without any specific treatment, the remaining 10% are at risk of developing chronic pain and disability. Chronic low back pain is a large burden on the healthcare system with high economic costs compounded by a substantial number of days of lost productivity annually.
An individual’s quality of life is likewise affected due to restricted mobility and the inability to partake in daily tasks. This often leads to decreased self-worth and depression. Unfortunately, the conventional methods of treatment are only modestly effective. Exercise is one of the few proven treatments for chronic low back pain, however its benefits are often very small. Other treatment options apart from medication, include spinal manipulation, acupuncture, massage, and yoga.
LBP is the most common condition for which complementary therapies are used with more than half of LBP patients in the United States utilizing complementary treatment options. Out of the 15 million of American adults who have practiced yoga at least once, 20% of those use yoga explicitly for back pain relief. In fact, even the American Pain Society’s guidelines recommend that clinicians consider offering yoga to patients with chronic LBP. Several of the factors contributing to the development of back pain can be addressed by a therapeutic yoga intervention. Our modern sedentary and stress-laden lifestyle has in part contributed to the rise in prevalence of back pain. The absence of physical activity weakens muscles, making them unable to support normal structural weight, and chronic stress produces short, tense muscles that limit range of motion, which can lead to back pain. In addition, the upsurge of obesity and occupations that require heavy lifting are all risk factors that can trigger back pain. Yoga may be a beneficial therapy for back pain because it involves physical movement along with added benefits of mental focus and stress-reduction.
Indeed, yoga exercises reduce physical impairment by increasing muscular strength and flexibility. Yoga also increases conscious body awareness and self-efficacy which can contribute to reducing the risk factors of poor posture and inappropriate movement and muscular activity. Yoga is particularly well-recognized as an effective method of reducing psychological stress. Specifically, yoga improves neuroendocrine function by normalizing the actions of the stress systems, including cortisol from the hypothalamic pituitary adrenal (HPA) axis and adrenaline and sympathetic activation from the autonomic nervous system. Although back pain is likely to be thought of as a purely muscular and mechanical disorder, the role of stress, mood, and pain perception contribute substantially to the experience of back pain. In fact, somewhat surprisingly, mindfulness and meditation have been shown to have therapeutic potential in treating back pain. Back pain patients in a recent MBSR (Mindfulness-Based Stress Reduction) intervention in 2015, published in the prestigious Journal of the American Medical Association, showed significant decrease of pain intensity along with improved physical and mental quality of life scores. Therefore, more traditional yoga styles/practices that include meditation as a key component are likely to be a better treatment strategy than the use of physical yoga exercises alone.
In the first meta-analysis and review of research on the efficacy of yoga for LBP, Cramer et al. included an analysis of 10 randomized controlled trials (RCTs) through January 2012 which encompassed 967 chronic low back pain patients. The majority of the studies had a low risk of bias, which gives us more confidence in the validity of the results. Six of the RCTs originated from the United States, 2 from the UK and 2 from India. Although the majority of patients were adult female Caucasians, the Indian studies included Asians, and some US studies looked at ethnic minorities, thereby making the results of the review applicable for the majority of LBP patients. The reviewed trials varied in the yoga styles used, but all compared yoga to control interventions and revealed strong evidence for short-term efficacy and moderate evidence of long-term impact of yoga on patients with chronic back pain. Surprisingly, there was no statistically-significant evidence for either short-term or long-term effects on health-related quality of life. On the other hand, yoga was not associated with serious adverse events which makes it a viable alternative to conventional drug treatment that often carries negative side-effects.
One of the studies reviewed was a landmark paper published in the Annals of Internal Medicine in 2005. In this 3-armed randomized control trial (RCT), 101 adults with chronic low back pain were treated with either 12-weekly sessions of yoga, therapeutic conventional exercise, or a self-care book, to determine relative efficacy. Interviewers who were blind to the treatment conducted telephone interviews at baseline and at 6, 12, and 26 weeks after the start of the study. The results of the study suggested that yoga is an effective treatment method for chronic LBP that had long-term benefits. Furthermore, medication use, which was similar among groups at baseline, decreased most sharply in the yoga group. Only 21% of participants in the yoga group reported medication use during the week before the 26-week interview compared with 50% in the exercise group and 59% in the book group. A common limitation to these behavioral intervention studies is observation bias but since in this case the interviewers were blind to the treatment assignments, this bias was minimized. Additionally, the large sample size allows for conclusive albeit preliminary assertions regarding the effectiveness and safety of yoga as an intervention in this population.
More recent research evaluating yoga for chronic back pain has investigated whether similar results are seen in more diverse populations. In 2009, Robert Saper’s research team at the Boston University School of Medicine, along with Karen Sherman and their colleagues, conducted a novel trial focusing on minority populations. This is significant because despite the increase in the popularity of yoga in the US, it is far less common among minorities and individuals with lower incomes or education. In this pilot RCT, 30 adults with a mean age of 44 years, 83% of them female and of racial or ethnic minorities, were randomly assigned to a standardized 12-week protocol of Hatha yoga classes or a usual care waitlist control group. The yoga participants had statistically significant reduction in pain intensity and medication after 12 weeks compared to the control group. Beyond the 12-week intervention period however, participant retention was poor and participants sought out treatments other than yoga, so it may be necessary to provide continuing yoga treatment support in this population.
Most of the studies to date have focused almost exclusively on chronic, nonspecific LBP, and therefore little is known about the efficacy of yoga in treating musculoskeletal conditions and pain in other areas of the back. In a study published in 2011 in the Yoga & Physical Therapy Journal, Lynn Schultz along with Sat Bir S. Khalsa and colleagues investigated the potential of yoga to ameliorate a broad range of back pain disorders. The study consisted of 24 adults with a complaint of chronic back pain who attended a 12-week program of weekly group yoga classes based on the system of the Krishnamacharya Healing Yoga Foundation (KHYF), a school well-known for its specialization in yoga therapy that includes asana, pranayama, core strengthening, meditation, bhavana (visualization), and mantra. Participants also practiced regularly at home and maintained a journal. The results demonstrated that the yoga classes significantly improved quality of life, decreased disability and pain, and improved physical functioning and mood. Subjects reported less depressive feelings, anger, fatigue, and confusion, indicating that yoga may not only improve back pain itself, but also the co-occurring symptoms.
In summary, studies to date have demonstrated the strong short-term and moderate long-term efficacy of yoga in treating a wide variety of back pain conditions without significant adverse side-effects. Future research should address the previous limitations of small sample sizes, moderate adherence, and lack of longer-term studies. They should also perhaps evaluate the dose response characteristics and the relative contribution to efficacy of the different components of yoga such as physical postures, breathing techniques, and meditation. These future trials would further improve our knowledge of the underlying mechanisms of yoga in back pain treatment and allow yoga therapists to devise more effective interventions.