What is yoga? What are the health benefits of yoga?

Yoga is a mind and body practice with historical origins in ancient Indian philosophy. Various styles of yoga combine physical postures, breathing techniques, and meditation or relaxation.

In 5,000 years of yoga history, the term "yoga" has gone through a renaissance in current culture, exchanging the loincloth for a leotard and pair of leggings.

Yoga has become popular as a form of physical exercise based upon asanas (physical poses) to promote bodily or mental control and well-being.

Contents of this article:

1. 1.  What is yoga?
2. 2.  What are the types of yoga?
3. 3   What are the health benefits of yoga?
4. 4.  What are the risks and side effects of yoga?

Fast facts on yoga

Here are some key points about yoga. More detail and supporting information is in the main article.

• The word "yoga" is derived from the Sanskrit root yuj meaning "to yoke or join together."
• A 2008 market study in Yoga Journal reports that some 16 million people in the US practice yoga and spend $5.7 billion a year on equipment.
• Hatha yoga is the type of yoga most frequently practiced in Western culture. Ha means "sun" and tha means "moon."
• There are many styles of yoga. The type of yoga class considered should be based on personal fitness level.
• According to the US Consumer Product Safety Commission, there were more than 7,369 yoga-related injuries treated in doctors' offices, clinics, and emergency rooms in 2010.
• Common yoga injuries include repetitive strain to and overstretching of the neck, shoulders, spine, legs, and knees.
• The American Academy of Orthopaedic Surgeons (AAOS) believes the rewards of basic yoga outweigh the potential physical risks.
• Yoga is defined as having eight branches or limbs: Yama, Niyama, Asana, Pranayama, Pratyhara, Dharana, Dhyana, Samadhi.
• Practicing yoga has many potential health benefits including relieving low back pain, assisting with stress management and increasing balance and flexibility.
• There is some evidence to suggest that pregnant women taking yoga classes are less likely to experience problems in later pregnancy and labor.

What is yoga?

History

There is no written record of the inventor of yoga. Yogis (yoga practitioners) practiced yoga long before any written account of it came into existence. Yogis over the millennia passed down the discipline to their students, and many different schools of yoga developed as the practice widened in global reach and popularity.⁶²

The postures that are now practiced in yoga classes were not originally a dominant component of yoga traditions in India. Fitness was not traditionally a chief aim of the practice.

Sanskrit, the Indo-European language of the Vedas, India's ancient religious texts, gave birth to both the literature and the technique of yoga.¹

The "Yoga Sutra," a 2,000-year-old treatise on yogic philosophy by the Indian sage Patanjali is a type of guidebook that gives guidance on how to gain mastery over the mind and emotions and advice on spiritual growth, providing the framework upon which all yoga practiced today is based. The Yoga Sutra is the earliest written record of yoga and one of the oldest texts in existence

The Sanskrit word "yoga" has several translations and can be interpreted in many ways. Many translations point toward translations of "to yoke," "join," or "concentrate" - essentially a means to unite or a method of discipline. A male who practices this discipline is called a yogi or yogin and a female practitioner, a yogini.

The postures that are now an integral part of health and fitness in many centers around the world were not originally a dominant component of yoga traditions in India. Fitness was not a chief aim of practice; focus was placed on other practices like pranayama (expansion of the vital energy by means of breath), dharana (focus, or placement of the mental faculty), and nada (sound).²

Yoga began to gain popularity in the West at the end of the 19th century, with an explosion of interest in postural yoga in the 1920s and 1930s, first in India and later in the West.

Philosophy

Yoga, in ancient times, was often referred to in terms of a tree with roots, trunk, branches, blossoms and fruits. Each branch of yoga has unique characteristics and represents a specific approach to life. The six branches are:³

1. Hatha yoga - physical and mental branch - involves asana and pranayama practice - preparing the body and mind
2. Raja yoga - meditation and strict adherence to the "eight limbs of yoga"
3. Karma yoga - path of service to consciously create a future free from negativity and selfishness caused by our actions
4. Bhakti yoga - path of devotion - a positive way to channel emotions and cultivate acceptance and tolerance
5. Jnana yoga - wisdom, the path of the scholar and intellect through study
6. Tantra yoga - pathway of ritual, ceremony or consummation of a relationship.

The 'eight limbs of yoga'

Raja yoga is traditionally referred to as ashtanga (eight-limbed) yoga, because there are eight aspects to the path to which one must attend. The eight limbs of ashtanga yoga are:⁴

1. Yama - ethical standards and sense of integrity. The five yamas are: ahimsa (nonviolence), satya (truthfulness), asteya (non-stealing), brahmacharya (continence) and aparigraha (non-covetousness)
2. Niyama - self-discipline and spiritual observances, meditation practices, contemplative walks. The five niyamas are: saucha (cleanliness), samtosa (contentment), tapas (heat, spiritual austerities), svadhyaya (study of sacred scriptures and of one's self) and isvara pranidhana (surrender to God)
3. Asana - integration of mind and body through physical activity
4. Pranayama- regulation of breath leading to integration of mind and body
5. Pratyahara - withdrawal of the senses of perception, the external world and outside stimuli
6. Dharana - concentration, one-pointedness of mind
7. Dhyana - meditation or contemplation - an uninterrupted flow of concentration
8. Samadhi - the quiet state of blissful awareness.

Chakras

The word chakra means "spinning wheel." According to the yogic view, chakras are a convergence of energy, thoughts, feelings, and the physical body. They determine how we experience reality from our emotional reactions, our desires or aversions, our level of confidence or fear, even the manifestation of physical symptoms.

When energy becomes blocked in a chakra, it is said to trigger physical, mental, or emotional imbalances that manifest in symptoms such as anxiety, lethargy, or poor digestion. The theory is to use asanas to free energy and stimulate an imbalanced chakra.

There are seven major chakras, each with their own associations:

Chakras are said to determine how we experience reality from our emotional reactions, our desires or aversions, our level of confidence or fear, even the manifestation of physical symptoms.

1. Sahasrara: the "thousand petaled" or "crown chakra" represents the state of pure consciousness. This chakra is located at the crown of the head and signified by the color white or violet. Sahasrara involves matters of inner wisdom and death of the body.
2. Ajna: the "command" or "third-eye chakra" represents a meeting point between two important energetic streams in the body. Ajna corresponds to the colors violet, indigo or deep blue, though it is traditionally described as white. The chakra is connected to the pituitary gland, growth and development.
3. Vishuddha: the "especially pure" or "throat chakra" is symbolized by the color red or blue. This chakra represents the home of speech and hearing, and the endocrine glands that control metabolism.
4. Anahata: the "unstruck" or "heart chakra" is related to the colors green or pink. Key issues involving Anahata involve complex emotions, compassion, tenderness, unconditional love, equilibrium, rejection and well-being.
5. Manipura: the "jewel city" or "navel chakra" is symbolized by the color yellow. This chakra is associated with the digestive system, along with personal power, fear, anxiety, opinion formation and introversion.
6. Svadhishthana: "one's own base" or "pelvic chakra" represents the home of the reproductive organs, the genitourinary system and the adrenals.
7. Muladhara: the "root support" or "root chakra" is located at the base of the spine in the coccygeal region. It is said to hold our instinctual urges around food, sleep, sex, and survival. It is also the realm of our avoidance and fears.

What are the types of yoga?

Modern forms of yoga have evolved into exercise focusing on strength, flexibility, and breathing to boost physical and mental well-being. There are many styles of yoga, and no style is more authentic or superior to another; the key is to choose a class appropriate for your fitness level. Types and styles of yoga may include:^5,6

Classes should be chosen depending on your fitness level and how much yoga experience you have.

• Ashtanga yoga: based on ancient yoga teachings but popularized in the 1970s, each of the six established sequences of postures rapidly link every movement to breath.
• Bikram yoga: held in artificially heated rooms at temperatures of nearly 105 degrees and 40% humidity, Bikram is a series of 26 poses and sequence of two breathing exercises.
• Hatha yoga: a generic term for any type of yoga that teaches physical postures. When a class is labeled as "hatha," it is usually a gentle introduction to the basic yoga postures.
• Iyengar yoga: focused on finding the proper alignment in each pose and using props such as blocks, blankets, straps, chairs and bolsters to do so.
• Jivamukti yoga: meaning, "liberation while living," jivamukti yoga emerged in 1984, incorporating spiritual teachings and vinyasa style practice. Each class has a theme, which is explored through yoga scripture, chanting, meditation, asana, pranayama, and music, and can be physically intense.
• Kripalu yoga: teaches practitioners to get to know, accept and learn from the body. In a Kriplau class, each student learns to find their own level of practice on a given day by looking inward. The classes usually begin with breathing exercises and gentle stretches, followed by a series of individual poses and final relaxation.
• Kundalini yoga: the Sanskrit word kundalini means coiled, like a snake. Kundalini yoga is a system of meditation directed toward the release of kundalini energy. A class typically begins with chanting and ends with singing, and in between features asana, pranayama, and meditation designed to create a specific outcome.
• Power yoga: an active and athletic style of yoga adapted from the traditional ashtanga system in the late 1980s.
• Prenatal yoga: yoga postures carefully adapted for expectant mothers. Prenatal yoga is tailored to help women in all stages of pregnancy or assist with getting back in shape post-birth.
• Restorative yoga: a relaxing method of yoga, spending a class in four or five simple poses using props like blankets and bolsters to sink into deep relaxation without exerting any effort in holding the pose.
• Sivananda: a system based on a five-point philosophy that proper breathing, relaxation, diet, exercise, and positive thinking work together to form a healthy yogic lifestyle. Typically uses the same 12 basic asanas, bookended by sun salutations and savasana poses.
• Vinyasa yoga: meaning, "flow," vinyasa classes are known for their fluid, movement-intensive practices. Classes are often choreographed to have smooth transitions from one pose to another, in an almost dance-like manner.
• Viniyoga: intended to be adaptable to any person, regardless of physical ability, viniyoga teachers much be highly trained and tend to be experts on anatomy and yoga therapy.
• Yin: a quiet, meditative yoga practice, also called taoist yoga. Yin yoga enables the release of tension in key joints: ankles, knees, hips, the whole back, neck, and shoulders. Yin poses are passive, meaning the muscles are to relax and let gravity do the work.

What are the health benefits of yoga?

Scientific trials of varying quality have been published on the health benefits and medical uses of yoga. Studies suggest that yoga is a safe and effective way to increase physical activity, especially strength, flexibility and balance. However, can the practice of yoga benefit other medical conditions? We take a look at medical evidence and current scientific research below.

Scientists and medical doctors pursuing yoga-related research are focusing on its potential ability to help prevent, heal, or alleviate specific conditions, such as heart disease, high blood pressure, carpal tunnel syndrome, asthma, diabetes, and symptoms of menopause, and its benefits as a technique for relieving stress and coping with chronic conditions or disabilities.⁷

Anxiety and depression

Mind-body medical interventions are commonly used to cope with depression, and yoga is one of the most commonly used mind-body interventions. Studies have taken place to assess systematically and meta-analyze the effectiveness of yoga for depression.

Yoga may be a promising way to reduce music performance anxiety and perhaps even prevent it in the future.

A 9-week course of yoga in veterans observed significant reductions in anxiety, depression, and suicidal ideation. Mental health functioning scores were also improved, but pain intensity and physical health functionality did not show improvements.³²

Hypercortisolemia is well-known in depression, and yoga has been demonstrated to reduce the parameters of stress, including cortisol levels. 

A study into the cortisol and antidepressant effects of yoga found that yoga might act at the level of the hypothalamus by its 'anti-stress' effects (reducing cortisol levels), to bring about relief in depression.³³

A systematic review and meta-analysis investigating yoga for depression examined 12 randomized controlled trials, including 619 participants. The researchers concluded that despite the methodological drawbacks of the included studies, yoga could be considered an ancillary treatment option for patients with depressive disorders and individuals with elevated levels of depression.³⁴

Professional musicians often experience high levels of stress, music performance anxiety (MPA), and performance-related musculoskeletal disorders (PRMDs). Given the fact that most professional musicians begin their musical training before the age of 12, it is important to identify interventions that will address these issues from an early age.³⁵

Results from a study suggest that yoga may be a promising way for adolescents to reduce MPA and perhaps even prevent it in the future. These findings also suggest a novel treatment modality that potentially might alleviate MPA and prevent the early disruption and termination of musical careers.

Arthritis

A systematic review of 9 studies regarding yoga as a complementary approach for osteoarthritis found positive changes in psychological or physiological outcomes related to arthritis.

Despite the limitations of not all of the studies using randomized controlled design or having smaller sample sizes, having different outcomes, having non-standardized yoga intervention, not using behavioral theory, and having varying lengths, yoga appears to be a promising modality for arthritis.⁴⁸

Asthma

When comparing asthmatics in a yoga group with those in a control group, those in the yoga group had a significant improvement in the proportion of hemoglobin and antioxidant superoxide, and significant decrease was found in total leukocyte count (TLC) and differential leukocytes count in comparison to control group.

The yoga group had more significant improvements in biochemical variables than the control group. Results show that yoga can be practiced as adjuvant therapy with standard inhalation therapy for a better outcome of asthma.¹⁵

However, in a systematic review assessing the effectiveness of yoga as a treatment for asthma, the researchers found the belief that yoga alleviates asthma is not supported by sound evidence and they indicate that further, more rigorous trials are warranted.¹⁶

Balance and falls

Falls amongst older people are a global health concern. Whilst falling is not a typical feature of aging, older people are more likely to fall and falls are a leading cause of death and disability.¹³

Yoga has been shown to help improve balance and prevent falls in older adults.

Yoga and tai chi have shown potential to improve balance and prevent falls in older adults. They also have potential to improve pain and quality of life.

In a 14-week yoga program, yoga demonstrated a decrease in fall incidence and a reduction in average pain scores, though not statistically significant. 

The results show positive changes to balance, pain and quality of life and a high level of interest through attendance amongst older participants. 

The results support offering tai chi and yoga to older people who are frail and dependent with physical and cognitive limitations.

Another study observing body balance and postural control in young adults determined that a 5-month hatha yoga training program could improve postural control significantly in healthy adults.¹⁴

Bipolar disorder

In a study of the benefits and risk of yoga in individuals with bipolar disorder, the participants reported positive emotional effects, particularly reduced anxiety, positive cognitive effects (e.g., acceptance, focus, or "a break from my thoughts"), or positive physical effects (e.g., weight loss, increased energy). Some respondents considered yoga to be significantly life changing. The most common negative effect of yoga was physical injury or pain.³⁶

Five respondents gave examples of specific instances of a yoga practice that they believed increased agitation or manic symptoms; five respondents gave examples of times that yoga increased depression or lethargy.

Breast cancer cognitive problems

Cancer survivors often report cognitive problems. Furthermore, decreases in physical activity typically occur over the course of cancer treatment. Although physical activity benefits cognitive function in non-cancer populations, evidence linking physical activity to cognitive function in cancer survivors is limited.⁴⁰

A study comparing a group with and without yoga intervention found that those who practiced yoga more frequently reported significantly fewer cognitive problems at a 3-month followup than those who practiced less frequently.

These findings suggest that yoga can effectively reduce breast cancer survivors' cognitive complaints and prompt further research on mind-body and physical activity interventions for improving cancer-related cognitive problems.

Breast cancer disability

Secondary arm lymphedema continues to affect at least 20% of women after treatment for breast cancer, along with pain and a range of motion restrictions requiring lifelong professional treatment and self-management.⁴¹

A pilot trial was aimed at determining the effect of yoga on women with stage one breast cancer-related lymphedema.

The 8-week yoga intervention reduced tissue induration of the affected upper arm and decreased the QOL subscale of symptoms. Arm volume of lymphedema and extra-cellular fluid did not increase. 

These benefits did not last on cessation of the intervention when arm volume of lymphedema increased. Further research trials with a longer duration, higher levels of lymphedema and larger numbers are warranted before definitive conclusions can be made.

Cancer-related fatigue

Fatigue is one of the most frequently reported, distressing side effects reported by cancer survivors and often has significant long-term consequences. Research indicates that yoga can produce invigorating effects on physical and mental energy, and thereby may improve levels of fatigue.

Studies have suggested that yoga interventions may be beneficial for reducing cancer-related fatigue in women with breast cancer.

An 8-week yoga exercise program assessed whether yoga can decrease anxiety, depression and fatigue in patients with breast cancer. Fatigue was effectively reduced in the study but did not reduce depression or anxiety.³⁷

The authors of the study conclude that oncology nurses should strengthen their clinical health education and apply yoga to reduce the fatigue experienced by patients with breast cancer who undergo adjuvant chemotherapy.

Another 12-week study with restorative Iyengar yoga intervention reduced inflammation-related gene expression in breast cancer survivors with persistent fatigue. These findings suggest that a targeted yoga program may have beneficial effects on inflammatory activity in this patient population, with potential relevance for behavioral and physical health.³⁸

A systematic review of yoga interventions on fatigue in cancer patients and survivors suggest that yoga interventions may be beneficial for reducing cancer-related fatigue in women with breast cancer; however, conclusions should be interpreted with caution as a result of levels of bias and inconsistent methods were used across studies.³⁹

Cardiovascular disease

A sedentary lifestyle and stress are major risk factors for cardiovascular disease. Since yoga involves exercise and is thought to help in stress reduction, it may be an effective strategy in the primary prevention of cardiovascular disease.

Across 11 identified trials with 800 participants, researchers found that the limited evidence in this field comes from small, short-term, low-quality studies. There is some evidence that yoga has favorable effects on diastolic blood pressure, HDL cholesterol and triglycerides, and uncertain effects on LDL cholesterol. These results should be considered as exploratory and interpreted with caution.⁴²

A meta-analysis on the subject revealed evidence for clinically important effects of yoga on most biological cardiovascular disease risk factors. Despite methodological drawbacks of the included studies, yoga can be considered as an ancillary intervention for the general population and patients with increased risk of cardiovascular disease.⁴³

Chronic neck pain

Assessment of the effects of a 9-week yoga intervention on chronic nonspecific neck pain found that neck-related disabilities were improved for at least 12 months after intervention completion. Sustained yoga practice was deemed the most important predictor of long-term effectiveness.²³

Chronic heart failure

A meta-analysis of the effects of yoga in patients with chronic heart failure suggested that yoga compared with control had a positive impact on peak VO2 and health-related quality of life.⁴⁴

Yoga could be considered for inclusion in cardiac rehabilitation programs. Larger randomized controlled trials are required to investigate the effects of yoga in patients with chronic heart failure further.

A randomized controlled trial indicated that the addition of yoga therapy to standard medical therapy for heart failure patients has a markedly better effect on cardiac function and reduced myocardial stress measured using N terminal pro B-type natriuretic peptide in patients with stable heart failure.⁴⁵

Chronic obstructive pulmonary disease

Currently, several studies have assessed the effect of yoga training on the management of chronic obstructive pulmonary disease. Five randomized controlled trials involving 233 patients suggested yoga training has a positive effect on improving lung function and exercise capacity and could be used as an adjunct pulmonary rehabilitation program in COPD patients.

However, further studies are needed to substantiate these preliminary findings and to investigate the long-term effects of yoga training.²⁴

Flexibility

Research on the effects of selected asanas in Iyangar yoga on flexibility over 6 weeks showed a significant increase in flexibility, indicating 6 weeks of single session yoga training may be effective in increasing erector spinae and hamstring flexibility.⁴⁷

Gastroesophageal reflux disease (GERD)

A case report assessed the effects of yoga on gastroesophageal reflux disease (GERD). The researchers indicate regular and proper use of yoga along with over-the-counter or prescribed proton pump inhibitors (PPI) can control the severe symptoms of GERD and can avoid or delay the necessity of invasive procedures.

The case report showed that with the regular practice of Kapalbhati and Agnisar kriya along with PPI, patients with hiatal hernia had improvement in severe symptoms of GERD which were initially refractory to PPI alone.⁴⁷

Hypertension

A few systematic reviews have scrutinized the quality of evidence and the strength of recommendation for yoga as a therapeutic means in the management of prehypertension and hypertension. Researchers have found that the effectiveness of yoga as a treatment of hypertension is encouraging but inconclusive.^25-27

Compared with exercise, no evidence was found for effects of yoga on systolic or diastolic blood pressure, and researchers point out that future research needs to focus on high quality clinical trials along with studies on the mechanisms of action of different yoga practices.

Low back pain

Several studies suggest yoga may be effective for chronic low back pain and have shown that yoga intervention in populations with chronic low back pain may be more effective than usual care for reducing both pain and medication use.¹⁷

Studies have indicated that 6 weeks of uninterrupted medical yoga therapy is a cost-effective early intervention for non-specific low back pain.

A randomized controlled study investigating medical yoga, exercise therapy and self-care advice concluded that 6 weeks of uninterrupted medical yoga therapy is a cost-effective early intervention for non-specific low back pain, when treatment recommendations are adhered to.¹⁸

The effect of yoga on pain, brain-derived neurotrophic factor, and serotonin in premenopausal women with chronic low back pain was investigated in a study. 

Participants practiced yoga three times a week for 12 weeks. The researchers propose that brain-derived neurotrophic factor may be one of the key factors mediating beneficial effects of yoga on chronic low back pain.¹⁹

A comparison trial monitored changes in pain intensity and health-related quality of life in nonspecific low back pain in those participating in Iyangar yoga or general exercise. The results suggest Iyengar yoga provides better improvement in pain reduction and improvement in quality of life than general exercise.²⁰

Virtual reality-based yoga programs such as Wii Fit Yoga have been shown to have positive effects on physical improvements in middle-aged female patients with low back pain. This program can be employed as a therapeutic medium for prevention and cure of low back pain.²¹

A meta-analysis of randomized controlled trials regarding the use of yoga for chronic low back pain agrees that yoga may be an efficacious adjunctive treatment for chronic low back pain. 

However, the researchers add that before any definitive conclusions can be drawn, a number of methodological concerns need to be addressed to determine whether yoga has specific treatment effects or offers any advantages over traditional exercise programs.²²

Menopause

In a community-based interventional study, the quality of life in menopausal women was greatly improved after an 18-week course of yoga practice. The researchers concluded that yoga is an effective complementary health approach for those suffering menopausal symptoms.⁸

Mental health

Physical activity has a positive effect on mental health and well-being. The aim of one study was to compare the effects of hatha yoga and resistance exercises on mental health and well-being in sedentary adults.³¹

Hatha yoga improved fatigue, self-esteem, and quality of life, whilst resistance exercise training improved body image. Hatha yoga and resistance exercise decreased depression symptoms at a similar level.

Hatha yoga and resistance exercise may affect different aspects of mental health and well-being.

Metabolic syndrome

An explorative study investigated metabolic responses to mental stress and yoga practices in yoga practitioners, non-yoga practitioners and individuals with metabolic syndrome (the medical term for a combination of diabetes, high blood pressure and obesity).³⁰

The results of the study support the findings of previous randomized trials that suggest regular yoga practice may mitigate against the effects of metabolic syndrome.

Migraine

A comprehensive study examining the effect of yoga on migraine showed significant clinical improvement in frequency and intensity of migraines in those taking part in yoga therapy. The researchers concluded that yoga therapy could be effectively incorporated as an adjuvant therapy in migraine patients.²⁸

Another study investigated the preventive effects of a three-month yoga intervention on endothelial function in patients with migraine.

The study revealed that yoga exercises, as a complementary treatment beside pharmacological treatments, could be potentially an effective way of improving vascular functions in migraineurs.²⁹

Mother and baby

Mother and baby yoga is becoming more and more popular as postpartum mothers discover the benefits of being able to "work out," bond with their baby and relax, all in one session.

Postnatal yoga or mother and baby yoga can help rebuild the weakened pelvic floor, strengthen the abdominal muscles and even alleviate back and neck pain while bonding with baby.

According to The Practicing Midwife, postnatal yoga can offer calm and a sense of well-being, helping mothers to improve and stabilize their emotional health and to bond. 

Additionally, the mother can focus on her relationship with her baby, rebuild the weakened pelvic floor, strengthen the abdominal muscles and even alleviate back and neck pain. 

For babies, yoga can aid digestion and alleviate colic, help to strengthen tiny limbs, improve sleep patterns, and enhance their ability to interact with their mother and other people.⁵⁵

Oxidative stress

Hypertension, especially in the elderly, is a strong risk factor for cardiovascular mortality and morbidity. Oxidative stress has been implicated as one of the underlying causes of hypertension.⁴⁵

A study found yoga to be an effective means to reduce oxidative stress and to improve antioxidant defense in elderly hypertensive individuals.

Posttraumatic stress

More than a third of the approximately 10 million women with histories of interpersonal violence in the US develop posttraumatic stress disorder (PTSD).

A study exploring the efficacy of yoga to increase affect tolerance and to decrease PTSD symptomatology found yoga significantly reduced symptoms of PTSD and improved the functioning of traumatized individuals.¹²

Pregnancy

Yoga is used for a variety of immunological, neuromuscular, psychological, and pain conditions. Recent studies indicate that it may be effective in improving pregnancy, labor, and birth outcomes.

The breathing and meditation techniques keep pregnant mothers healthy and relaxed, and provide the mental focus to aid childbirth. Some postures are chosen specifically to help encourage an optimal fetal position.⁵⁰

In a survey ascertaining the opinions, practices and knowledge about exercise, including yoga, during pregnancy:⁵¹

Yoga may help improve stress levels, quality of life, and labor parameters such as comfort, pain, and duration in pregnant women.

• 86% of women responded that exercise during pregnancy is beneficial
• 83% felt it was beneficial to start prior to pregnancy
• 62% considered walking to be the most beneficial form of exercise
• 64% of respondents were currently exercising during pregnancy
• 51% exercised 2-3 times a week
• 65% considered yoga to be beneficial
• 40% had attempted yoga before pregnancy.

Another study tested the efficacy of yoga as an intervention for reducing maternal anxiety during pregnancy.

A single session of yoga reduced both subjective and physiological measures of state anxiety and this class-induced reduction in anxiety remained at the final session of the intervention. Antenatal yoga seems to be useful for reducing women's anxieties toward childbirth and preventing increases in depressive symptomatology.⁵²

Yoga group participants show fewer postpartum but not antepartum depressive symptoms than control group participants. Findings indicate that prenatal Hatha yoga may improve current mood and may be effective in reducing postpartum depressive symptoms.⁵³

A systematic review of yoga for pregnant women showed that studies indicate that yoga may produce improvements in stress levels, quality of life, aspects of interpersonal relating, autonomic nervous system functioning, and labor parameters such as comfort, pain, and duration. However, they conclude that more randomized controlled trials are needed to provide more information regarding the utility of yoga interventions for pregnancy.⁵⁴

Restless legs syndrome

Restless legs syndrome is a common and highly burdensome sleep disorder.

Women aged 32-66 years with restless legs syndrome completed 16 yoga classes. At follow-up, participants demonstrated striking reductions in restless syndrome symptoms and symptom severity, with symptoms decreasing to minimal/mild in all but one woman and no participant scoring in the severe range by week 8. Participants also showed significant improvements in sleep, perceived stress, and mood.⁵⁸

Sleep

The aging process is associated with physiological changes that affect sleep. In older adults, undiagnosed and untreated insomnia may cause impaired daily function and reduced quality of life. Insomnia is also a risk factor for accidents and falls that are the main cause of accidental deaths in older adults.

Compared with controls, the yoga group showed significant improvements in a range of subjective factors, including:⁵⁷

• Overall sleep quality
• Sleep efficiency
• Sleep latency and duration
• Self-assessed sleep quality
• Fatigue
• General well-being
• Depression
• Anxiety
• Stress
• Tension
• Anger
• Vitality
• Function in physical, emotional, and social roles.

Yoga was shown to be safe and improved sleep and quality of life in a group of older adults with insomnia. Outcomes depended on practice compliance.

Stress management

Several studies have looked at yoga as a model for stress management. In a study observing the effects of 10 weeks of classroom-based yoga on cortisol and behavior in second and third-grade students, cortisol decreased significantly and improvements in students' behavior improved. The results suggest that school-based yoga may be advantageous for stress management and behavior.⁹

Studies suggest that school-based yoga may assist with stress management and the behavior of children.

Equally, another study addresses how children and young people in today's world face numerous expectations and constant stimulation through the Internet and other media and communication technologies. 

One reason children experience stress and mental health challenges is that globalization exposes the youth all over the world to various new demands, standards, and options. 

The researchers examined yoga as a potential tool for children to deal with stress and found that yoga may help children and young people cope with stress and as a result, contribute positively to balance in life, well-being, and mental health.¹⁰

One study evaluated the influence of hatha yoga practice on the distress of women before beginning a course of in vitro fertilization (IVF). Of the 143 female participants, 45 attended hatha yoga and 75 did not. Data suggest that psychological support and practice of hatha yoga before IVF is associated with distress reduction.¹¹

Urinary incontinence

Yoga has been shown to reduce inflammation and may help improve symptoms of urge urinary incontinence. More research is necessary to demonstrate the effectiveness of yoga to reduce urge urinary incontinence symptom burden and improve quality of life.⁴⁶

Weight management

A comparative controlled trial compared the effects of yoga and walking for overweight and obese adults.

Both groups showed a significant decrease in BMI, waist circumference, hip circumference, lean mass, body water, and total cholesterol. The yoga group increased serum leptin and decreased LDL cholesterol. The walking group decreased serum adiponectin and triglycerides.⁴⁹

Both yoga and walking improved anthropometric variables and serum lipid profile in overweight and obese persons.

The prevalence of yoga research in western health care is increasing. The marked increase in volume indicates the need for more systematic analysis of the literature in terms of quality and results.⁶¹

What are the risks and side effects of yoga?

Yoga is low-impact and safe for healthy people when practiced appropriately under the guidance of a well-trained instructor.

Yoga should never be used to replace standard medical care. If you have a medical condition, check with your doctor before beginning yoga classes.

Injury due to yoga is an infrequent barrier to continued practice, and severe injury due to yoga is rare.^58,59

Women who are pregnant and people with certain medical conditions, such as high blood pressure,glaucoma, and sciatica, should modify or avoid some yoga poses.

Beginners should avoid extreme practices such as headstand, lotus position and forceful breathing.

Individuals with medical preconditions should work with their physician and yoga teacher to appropriately adapt postures; patients with glaucoma should avoid inversions and patients with compromised bone should avoid forceful yoga practices.⁶⁰

Do not use yoga to replace conventional medical care or to postpone seeing a health care provider about pain or any other medical condition. If you have a medical condition, talk to your health care provider before starting yoga.

References:

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3.        Yoga Journal The roots of yoga: ancient + modern, accessed 2 December 2014.

4.        Yoga Journal The branches of yoga, accessed 2 December 2014.

5.        Yoga Journal Get to know the 8 limbs of yoga, accessed 2 December 2014.

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