Iyengar Yoga

B.K.S. Iyengar and his teacher

Iyengar Yoga is named for Bellur Krishnamachar Sundararaja Iyengar, born on December 14, 1918, in Bellur, India, who died on August 20, 2014, at the age of 95 according to Iyengar Yoga UK. The Iyengar Yoga National Association of the United States (IYNAUS) says he began studying yoga at 15 with his brother-in-law and guru, T. Krishnamacharya, who sent him to fill a teaching position in Pune in 1937.

The two associations differ slightly in how they state his age at death, 95 and 96, so the sources cannot be reconciled from the pages reviewed here. Both are published by teaching bodies that carry his name, and they function as organizational accounts rather than independent biography.

Spread to Europe and the United States

IYNAUS reports that Iyengar taught in Europe from 1954 at the invitation of the violinist Yehudi Menuhin and first taught in the United States in 1956 in Ann Arbor, Michigan. Both associations describe his book Light on Yoga as continuously in print since 1966, and IYNAUS calls it an international bestseller. Iyengar Yoga UK adds that he taught for more than 75 years on all five continents and brought yoga to the West in the 1970s, a summary that differs from the dates IYNAUS gives for his earlier teaching abroad.

The institute in Pune

The Ramamani Iyengar Memorial Yoga Institute (RIMYI) in Pune was established on January 19, 1975, according to the institute's own page, and it is dedicated to Ramamani Iyengar, the wife of B.K.S. Iyengar. IYNAUS states that she died in 1973. The institute's page lists B.K.S. Iyengar, Geeta S. Iyengar and Prashant S. Iyengar as directors at the time of its copyright date of 2009; Iyengar Yoga UK now names his son Prashant Iyengar and granddaughter Abhijata Sridhar Iyengar as directors.

Names and usage

The method is called Iyengar Yoga, with capital letters, by the associations that certify its teachers and by the Pune institute, which describes itself as the heart and soul of Iyengar Yoga. Research papers on the method use the spellings Iyengar yoga or Iyengar-style yoga. The sources reviewed do not define a separate Sanskrit term for the method itself.

Teaching bodies use the term asana for a posture and pranayama for breath practices. IYNAUS lists assessment in demonstrated practice of asanas and pranayamas as one of three assessment categories. Pranayama and Hatha Yoga have their own Machipedia pages, and Yoga is covered in a separate page that places this method among others.

Relation to other yoga styles

Machipedia covers the wider family of named approaches on the page Yoga Styles, where Iyengar Yoga is listed as one member beside Ashtanga Yoga, Restorative Yoga and others. The Cochrane review of yoga for chronic low back pain groups trials by the style label their authors gave, and states that most trials used Iyengar, hatha or viniyoga yoga, so researchers treat these as separate labels within the broader category of yoga.

A distinction matters for reading research. Findings for Iyengar Yoga should not be assumed to hold for other styles, and findings from general yoga reviews should not be assumed to hold for this method. The sources reviewed here do not compare Iyengar Yoga directly with another named style.

Props and the Iyengar approach

IYNAUS says props allow people of all ages and all stages of health to perform asanas with greater ease and lists mats, blocks, belts, blankets and chairs, along with wooden props designed by B.K.S. Iyengar. Iyengar Yoga UK likewise credits him with inventing props such as blankets and belts that help students of all skill levels practice asanas safely. These are statements by teaching bodies about their own method and have not been tested as claims about safety.

The pages reviewed do not describe alignment instruction, hold times or sequencing in detail, so this page does not characterize them. Bolsters and wall ropes, often mentioned in popular accounts, were not named by the institute or association pages that were opened.

How classes appear in trials

Trial reports give a view of delivery. The neck pain trial by Michalsen and colleagues used weekly 90-minute Iyengar classes over 9 weeks, and the depression dosing study by Streeter and colleagues used 90-minute classes plus homework, two or three times a week for 12 weeks, combined with coherent breathing. The 2009 low back pain trial by Williams and colleagues used biweekly classes over 24 weeks. A pregnancy study of modified Iyengar yoga used a 90-minute weekly class for 12 weeks led by certified instructors.

What the associations and institute state

The institute describes itself as a place where students from around the world come to receive the essence of yoga and learn life's values. IYNAUS states that its props allow people of all ages and stages of health to practice asanas, and describes Iyengar as having overcome deadly childhood illnesses. The pages reviewed do not list specific conditions the method is intended to address.

Conditions studied in trials

Researchers have tested Iyengar Yoga for chronic low back pain, chronic neck pain, major depressive disorder and, in one modified form, anxiety and labor pain in pregnancy. These are research questions chosen by investigators and should not be read as uses endorsed by the institute or by certifying bodies. The next section describes what each set of studies found and where it falls short.

Chronic low back pain

Williams and colleagues reported in 2005 a randomized trial of 60 adults with nonspecific chronic low back pain, comparing 16 weeks of Iyengar yoga with an educational control. Of those enrolled, 42 completed the study. The yoga group showed reductions of about 64 percent in pain intensity, 77 percent in functional disability and 88 percent in pain medication use at post-intervention and 3-month follow-up. The authors called the data preliminary and noted participants were mostly self-referred with mild pain.

A larger trial in 2009 randomized 90 adults to 24 weeks of biweekly Iyengar yoga classes (43) or standard medical care (47). At 24 weeks the yoga group had greater reductions in disability and pain intensity and lower depression scores, and the effects were somewhat smaller at the 6-month follow-up. The comparison was with usual care, not another exercise.

The 2022 Cochrane review of 21 trials (2,223 participants) found that yoga compared with no exercise produced small improvements in back-related function and pain that the review considers clinically unimportant, and probably made little or no difference to function compared with other back-focused exercise. It states that most trials used Iyengar, hatha or viniyoga yoga and lists both Williams trials among the included studies. These findings apply to yoga in general, not to Iyengar Yoga alone.

Chronic neck pain

Michalsen and colleagues randomized 77 adults with chronic neck pain to 9 weeks of Iyengar yoga or a self-care and exercise program. Resting pain on a 100-mm scale fell from 44.3 to 13.0 with yoga and from 41.9 to 34.4 with self-care, a group difference of 20.1 points. The authors called it preliminary, and 23 participants were lost to follow-up. Cramer and colleagues randomized 51 adults to yoga or home exercise and found a 13.9 mm lower pain score with yoga.

A 2016 systematic review of three randomized trials, two of them Iyengar trials, rated all three at high risk of bias and noted the lack of blinding, subjective outcomes and absence of long-term follow-up. The review described evidence suggesting yoga may be beneficial and could not support firm conclusions.

Depression, pregnancy and other conditions

Streeter and colleagues compared high-dose (three classes weekly) and low-dose (two classes weekly) Iyengar yoga plus coherent breathing over 12 weeks in 30 adults with major depressive disorder. Depression scores fell in both groups with no significant between-group difference in response or remission. There was no control arm, so the change cannot be attributed to the method.

A study of 59 third-trimester primigravid women in Indonesia reported lower labor pain and anxiety scores with modified Iyengar yoga than in a no-yoga group. The design measured outcomes only after the intervention, did not describe randomization or blinding, and sampled a single private midwifery practice, so it supports a research question rather than a conclusion. The sources reviewed did not include a large trial of Iyengar Yoga for any other condition.

Adverse events reported for yoga

A systematic review of published case reports and case series covered 76 cases through February 2013. Musculoskeletal events were most common (about 35 percent), followed by nervous system and eye events; 15 cases recovered fully, 9 partly, 1 not, and 1 was fatal. Headstand, shoulder stand, lotus position and forceful breathing were most often named. The authors say case reports cannot give incidence, reporting quality was low, and few reports named the yoga style, so Iyengar Yoga cannot be separated from the findings.

A 2015 review of randomized trials found 94 of 301 trials reported adverse events and found no clear difference from usual care or exercise, but higher odds of nonserious and intervention-related events compared with psychological or educational control groups. The Cochrane back pain review found more adverse events than no exercise but a similar risk to other exercise, mainly increased back pain, with no serious adverse events attributed to yoga in its trials.

Medical conditions, props and pregnancy

The case report review advises that people with medical conditions adapt postures with their physician and teacher, that beginners avoid extreme practices, and that people with glaucoma avoid inversions. It does not discuss the Iyengar prop-based approach. Teaching bodies state that props allow practice at all stages of health, but no source reviewed tested whether props lower injury rates.

For pregnancy, the sources reviewed contain one small trial of modified Iyengar yoga and no safety guidance, so this page makes no statement on suitability. Yoga does not replace medical care for back pain, depression or pregnancy, and persistent or worsening symptoms warrant a clinician.

Teacher training and certification

IYNAUS lists five teacher certification levels, from Level 1 (formerly Introductory 1 and 2) to Level 5, assessed by RIMYI in India, and says teachers must pass assessment of asana and pranayama practice, a written exam and demonstrated teaching skills. Iyengar Yoga UK says candidates need at least three years of regular classes and a good standard in Level 1 asanas, followed by mentorship of at least three years, with levels in effect from July 1, 2020.

These describe the associations' own voluntary standards in the United States and the United Kingdom. The pages reviewed do not name an independent external accreditor, and no source reviewed compares outcomes for certified and uncertified teachers.