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Yoga Before engaging in any complementary medical technique, you should be aware that many of these techniques have not been evaluated in scientific studies. Often, only limited information is available about their safety and effectiveness. Each state and each discipline has its own rules about whether practitioners are required to be professionally licensed. If you plan to visit a practitioner, it is recommended that you choose one who is licensed by a recognized national organization and who abides by the organization's standards. It is always best to speak with your primary health care provider before starting any new therapeutic technique.
Yoga is an ancient system of relaxation, exercise and healing with origins in Indian philosophy. Yoga has been described as "the union of mind, body, and spirit." The philosophy of yoga is sometimes pictured as a tree with eight branches: - Pranayama (breathing exercises)
- Asana (physical postures)
- Yama (moral behavior)
- Niyama (healthy habit)
- Dharana (concentration)
- Pratyahara (sense withdrawal)
- Dhyana (contemplation)
- Samadhi (higher consciousness)
There are several types of yoga, including hatha yoga, karma yoga, bhakti yoga and raja yoga. These types vary in the proportions of the eight branches. In the United States and Europe, hatha yoga is commonly practiced, including pranayama and asana. Yoga is often practiced by healthy individuals with the aim to achieve relaxation, fitness and a healthy lifestyle. Yoga may be practiced alone, or with a group. Yoga classes and video tapes are available. There are no official or well-accepted licensing requirements for yoga practitioners.
It has been hypothesized that yoga may benefit health through mind-body interactions. In yoga, poses are held for varying lengths of time using gravity, leverage and tension. Breathing techniques are also used. Rapid breathing (kapalabhati) and slow breathing (nadi suddhi) may be practiced along with stretching exercises. Yoga has been shown to reduce heart rate and blood pressure, increase lung capacity, increase the amount of time you can hold your breath, improve muscle relaxation and body composition, cause weight loss and increase overall physical endurance. Yoga may affect levels of brain or blood chemicals, including monoamines, melatonin, dopamine, stress hormones (cortisol) and GABA (gamma-aminobutyric acid). Changes in mental functions such as attention, cognition, processing of sensory information and visual perception have been described in some research studies in humans.
Scientists have studied yoga for the following health problems: Anxiety and stress (in healthy individuals) | Several studies report that yoga may reduce anxiety and stress and improve mood in healthy people who practice yoga several times per week for 30 to 60 minutes. However, most studies have not been well designed, and different yoga techniques have been used. | Anxiety disorders, obsessive-compulsive disorder | Several studies in humans report benefits of yoga in the treatment of anxiety disorders and obsessive-compulsive disorder. Kundalini meditation and relaxation have been used for these conditions. Further well-designed studies are needed before a firm conclusion can be drawn. | Asthma | Multiple studies in humans suggest benefits of yoga (such as breathing exercises) when used in addition to other therapies for mild-to-moderate asthma (such as prescription drugs, diet or massage). Some research demonstrates improved lung function, overall fitness and airway sensitivity and reduced need for asthma drugs, but there is also research showing no significant changes. Many of these studies are poorly designed, and because of conflicting evidence, better research is needed before a strong recommendation can be made. | High blood pressure (hypertension) | Several studies in humans report benefits of yoga in the treatment of high blood pressure. However, many of these studies are not well designed. It is not clear if yoga is better than other forms of exercise for blood pressure control. Additional research is needed.
Yoga practitioners sometimes recommend that patients with high blood pressure avoid certain positions, such as headstands or shoulder stands (inverted asanas), which may temporarily increase blood pressure. | Heart disease | Several studies in humans suggest that yoga may benefit people with heart disease. Along with positive lifestyle changes, yoga may help decrease angina (chest pain) and improve ability to exercise. Yoga may decrease risk factors for heart disease, including high blood pressure, cholesterol and blood sugar levels. It is unclear if yoga reduces the risk of heart attack or death or if yoga is better than any other form of exercise therapy or lifestyle or dietary change. Yoga may be a useful addition to standard therapies (such as prescription blood pressure or cholesterol-lowering drugs) in people at risk of heart attack. Further research is necessary before a strong recommendation can be made.
People with heart disease should consult their health care provider before starting any new exercise program. | Depression | Several studies in humans support the use of yoga for depression in both children and adults. Studies have compared yoga with low-dose antidepressants, electric shock therapy or no treatment. Although this preliminary research is promising, better studies are needed that examine people with clearly defined clinical depression. | Seizure disorder (epilepsy) | Several studies in humans report a reduction in the number of monthly seizures with the use of sahaja yoga, when it is used with standard antiseizure drugs. This research is preliminary, and better studies are necessary before a firm conclusion can be drawn. | Carpal tunnel syndrome | Yoga therapy has been studied for carpal tunnel syndrome, but it is not clear if there are beneficial effects. Further research is needed before a recommendation can be made. | Diabetes | Early studies in humans report that daily yoga may improve control of blood sugar levels in people with type 2 diabetes, when added to standard drug therapy. However, this research is not high quality. It is not clear if yoga is better than any other forms of exercise therapy for this purpose. More research is necessary before a recommendation can be made.
People with heart disease should consult their health care provider before starting any new exercise program. | Headache | Preliminary research reports that yoga may reduce the intensity and frequency of tension or migraine headaches, decreasing the need for pain-relieving drugs. However, better studies are needed before any recommendation can be made. | Insomnia | There is limited study in humans of yoga in the treatment of insomnia. Further research is needed before a recommendation can be made. | Memory | There is limited study in humans of yoga for improving memory. Most research focuses on memory in children. Better studies are needed before a recommendation can be made. | Posture | Preliminary studies in humans report that yoga may improve posture in children. However, better-designed studies are needed before any conclusion can be drawn. | Lung disease | Limited study in humans evaluates yoga as a treatment for lung conditions such as bronchitis, fluid around the lungs (pleural effusion) or airway obstruction. Well-designed research is necessary before a recommendation can be made. | Mental retardation | There is limited study of yoga therapy in children with mental retardation. Preliminary research reports improvements in IQ and social behavior. Better studies are needed to confirm these results and to evaluate the effects of yoga in mentally retarded adults. | Substance abuse | Preliminary research reports that yoga may be beneficial when added to standard therapies for the treatment of heroin or alcohol abuse. However, better studies are needed before any recommendation can be made. | Ringing in the ears (tinnitus) | One study reports that yoga therapy does not improve tinnitus. Although relaxation may theoretically benefit this condition, additional research is needed before a recommendation can be made. | Antioxidant | A small study in men showed that yogic breathing may have an antioxidant effect. Larger well-designed studies are needed before conclusions can be drawn. | Cancer | A small study in breast and prostate cancer patients reported enhanced quality of life, decreased stress symptoms and changes in cancer-related immune cells after patients received relaxation, meditation and gentle yoga therapy. Yoga is not recommended as a sole treatment for cancer but may be helpful as an adjunct therapy. |
Yoga has been suggested for many other uses, based on tradition or on scientific theories. However, these uses have not been thoroughly studied in humans, and there is limited scientific evidence about safety or effectiveness. Some of these suggested uses are for conditions that are potentially life-threatening. Consult with a health care provider before using yoga for any use. Addiction
Attention-deficit hyperactivity disorder
Back pain
Childbirth preparation
Chronic pain
Chronic urologic disorders (kidney, bladder)
Fibromyalgia
Heart attack prevention, treatment and rehabilitation
HIV/AIDS
Joint pain or stiffness
Low oxygen in the blood (hypoxemia)
Lung infections
Menopause
Multiple sclerosis | Muscle pain and tension
Neck pain
Occupational stress
Osteoarthritis
Osteoporosis
Premenstrual syndrome
Rehabilitation
Rheumatoid arthritis
Scoliosis/hyperkyphosis (extreme curvature of the spine)
Seasonal affective disorder
Sex offender rehabilitation
Shortness of breath
Slow (delayed) ejaculation
Stomach upset
Thyroid disease
Well-being |
Yoga has been well tolerated in studies, with few side effects reported in healthy people. Yoga is believed to be safe during pregnancy and breast-feeding when practiced under the guidance of expert instruction (the popular Lamaze techniques are based on yogic breathing). However, yoga poses that put pressure on the uterus, such as abdominal twists, should be avoided during pregnancy. The following have been rarely reported: - Nerve or vertebral disc damage — Caused by prolonged postures, sometimes involving the legs
- Eye damage and blurred vision, including worsening of glaucoma — Caused by increased eye pressure with headstands
- Stroke or blood vessel blockage — Caused by decreased blood flow to the brain or other body parts from postures
There is one report of a teen-age girl who died of obstructed breathing associated with mouth-to-mouth yoga (in which one person breathes into another person's mouth using yoga breathing techniques). However, a long-acting barbiturate (which can cause decreased breathing) may have been partially at fault. Chronic cheilitis (inflammation of the lips) and persistent reflux have been reported in yoga instructors with unclear relationship to this modality. People with disc disease, fragile or atherosclerotic neck arteries, a risk of blood clots, extremely high or low blood pressure, glaucoma, retinal detachment, ear problems, severe osteoporosis or cervical spondylitis should avoid some yoga poses. Certain yoga breathing techniques should be avoided in people with heart or lung disease. Some experts advise caution in people with a history of psychotic disorders (such as schizophrenia), because there is a risk of worsening symptoms, although this has not been clearly shown in studies. You should speak with your health care provider before starting yoga or any new exercise regimen.
Yoga has been suggested for many conditions. There is preliminary evidence that yoga may be beneficial when it is added to standard treatments for several conditions, including anxiety disorders or stress, asthma, high blood pressure, heart disease and depression. It is not clear if yoga is any more or less effective than other forms of exercise. Damage to nerves or discs in the back have been reported, and caution is warranted in some individuals. Speak with your health care provider if you are considering starting yoga, or any new exercise program.
The information in this monograph was prepared by the professional staff at Natural Standard, based on thorough systematic review of scientific evidence. The material was reviewed by the Faculty of the Harvard Medical School with final editing approved by Natural Standard.
- Natural Standard: An organization that produces scientifically based reviews of complementary and alternative medicine (CAM) topics
- National Center for Complementary and Alternative Medicine (NCCAM): A division of the U.S. Department of Health & Human Services dedicated to research
Selected Scientific Studies: Yoga Natural Standard reviewed more than 350 articles to prepare the professional monograph from which this version was created. Some of the more recent studies are listed below: - Behera D. Yoga therapy in chronic bronchitis. J Assoc Physicians India 1998;46(2):207-208.
- Bhattacharya S, Pandey US, Verma NS. Improvement in oxidative status with yogic breathing in young healthy males. Indian J Physiol Pharmacol 2002;Jul, 46(3):349-354.
- Biswas R, Dalal M. A yoga teacher with persistent cheilitis. Int J Clin Pract 2003;May, 57(4):340-342.
- Biswas R, Paul A, Shetty KJ. A yoga teacher with persistent reflux symptoms. Int J Clin Pract 2002;Nov, 56(9):723.
- Carlson LE, Speca M, Patel KD, Goodey E. Mindfulness-based stress reduction in relation to quality of life, mood, symptoms of stress, and immune parameters in breast and prostate cancer outpatients. Psychosom Med 2003;Jul-Aug, 65(4):571-581.
- Chaudhary AK, Bhatnagar HN, Bhatnagar LK, et al. Comparative study of the effect of drugs and relaxation exercise (yoga shavasan) in hypertension. J Assoc Physicians India 1988;36(12):721-723.
- Chusid J. Yoga foot drop. JAMA 1971;217(6):827-828.
- Cooper S, Oborne J, Newton S, et al. Effect of two breathing exercises (Buteyko and pranayama) in asthma: a randomized controlled trial. Thorax 2003;Aug, 58(8):674-679. Comment in: Thorax 2003;Aug, 58(8):649-650.
- Corrigan GE. Fatal air embolism after yoga breathing exercises. JAMA 1969;210(10):1923.
- Damodaran A, Malathi A, Patil N, et al. Therapeutic potential of yoga practices in modifying cardiovascular risk profile in middle aged men and women. J Assoc Physicians India 2002;May, 50(5):633-640. Comment in: J Assoc Physicians India 200;May, 50(5):631-632.
- Delmonte MM. Case reports on the use of meditative relaxation as an intervention strategy with retarded ejaculation. Biofeedback Self Regul 1984;9(2):209-214.
- Fahmy JA, Fledelius H. Yoga-induced attacks of acute glaucoma: a case report. Acta Ophthalmol (Copenh) 1973;51(1):80-84.
- Fluge T, Richter J, Fabel H, et al. [Long-term effects of breathing exercises and yoga in patients with bronchial asthma]. Pneumologie 1994;48(7):484-490.
- Fong KY, Cheung RT, Yu YL, et al. Basilar artery occlusion following yoga exercise: a case report. Clin Exp Neurol 1993;30:104-109.
- Garfinkel MS, Schumacher HR, Husain A, et al. Evaluation of a yoga based regimen for treatment of osteoarthritis of the hands. J Rheumatol 1994;21(12):2341-2343.
- Garfinkel MS, Singhal A, Katz WA, et al. Yoga-based intervention for carpal tunnel syndrome: a randomized trial. JAMA 1998;280(18):1601-1603.
- Gerritsen AA, de Krom MC, Struijs MA, et al. Conservative treatment options for carpal tunnel syndrome: a systematic review of randomised controlled trials. J Neurol 2002;Mar, 249(3):272-280.
- Greendale GA, McDivit A, Carpenter A, et al. Yoga for women with hyperkyphosis: results of a pilot study. Am J Public Health 2002;Oct, 92(10):1611-1614.
- Gura ST. Yoga for stress reduction and injury prevention at work. Work 2002;19(1):3-7.
- Hanus SH, Homer TD, Harter DH. Vertebral artery occlusion complicating yoga exercises. Arch Neurol 1977;34(9):574-575.
- Janakiramaiah N, Gangadhar BN, Murthy PJ, et al. Antidepressant efficacy of sudarshan kriya yoga (SKY) in melancholia: a randomized comparison with electroconvulsive therapy (ECT) and imipramine. J Affect Disorders 2000;57:255-259.
- Khumar SS, Kaur P, Kaur MS. Effectiveness of Shavasana on depression among university students. Indian J Clin Psych 1993;20(2):82-87.
- Klatz RM, Goldman RM, Pinchuk BG, et al. The effects of gravity inversion procedures on systemic blood pressure, intraocular pressure, and central retinal arterial pressure. J Am Osteopath Assoc 1983;82(11):853-857.
- Konar D, Latha R, Bhuvaneswaran JS. Cardiovascular responses to head-down-body-up postural exercise (Sarvangasana). Indian J Physiol Pharmacol 2000;44(4):392-400.
- Madanmohan, Udupa K, Bhavanani AB, et al. Modulation of cold pressor-induced stress by shavasan in normal adult volunteers. Indian J Physiol Pharmacol 2002;Jul, 46(3):307-312.
- Malathi A, Damodaran A. Stress due to exams in medical students: role of yoga. Indian J Physiol Pharmacol 1999;43(2):218-224.
- Malhotra V, Singh S, Singh KP, et al. Study of yoga asanas in assessment of pulmonary function in NIDDM patients. Indian J Physiol Pharmacol 2002;Jul, 46(3):313-320.
- Manocha R, Marks GB, Kenchington P, et al. Sahaja yoga in the management of moderate to severe asthma: a randomized controlled trial. Thorax 2002;Feb, 57(2):110-115. Comment in: Thorax 2003;Sep, 58(9):825-826.
- Malathi A, Damodaran A. Stress due to exams in medical students: role of yoga. Indian J Physiol Pharmacol 1999;43(2):218-224.
- Mohan M, Saravanane C, Surange SG, et al. Effect of yoga type breathing on heart rate and cardiac axis of normal subjects. Indian J Physiol Pharmacol 1986;30(4):334-340.
- Monro R, Power J, Coumar A, et al. Yoga therapy for NIDDM: a controlled trial. Complement Med Res 1992;6(2):66-68.
- Murugesan R, Govindarajulu N, Bera TK. Effect of selected yogic practices on the management of hypertension. Indian J Physiol Pharmacol 2000;44(2):207-210.
- Nagarathna R, Nagendra HR. Yoga for bronchial asthma: a controlled study. Br Med J 1985;291(6502):1077-1079.
- Panjwani U, Gupta HL, Singh SH, et al. Effect of sahaja yoga practice on stress management in patients of epilepsy. Indian J Physiol Pharmacol 1995;39(2):111-116.
- Panjwani U, Selvamurthy W, Singh SH, et al. Effect of sahaja yoga practice on seizure control and EEG changes in patients of epilepsy. Indian J Med Res 1996;103:165-172.
- Patel C, North WS. Randomised controlled trial of yoga and bio-feedback in management of hypertension. Lancet 1975;2:93-95.
- Patel C. 12-Month follow-up of yoga and bio-feedback in the management of hypertension. Lancet 1975;1(7898):62-64.
- Prakasamma M, Bhaduri A. A study of yoga as a nursing intervention in the care of patients with pleural effusion. J Adv Nurs 1984;9(2):127-133.
- Ripoll E, Mahowald D. Hatha Yoga therapy management of urologic disorders. World J Urol 2002;Nov, 20(5):306-309. Epub 2002 Oct 24.
- Russell WR. Yoga and vertebral arteries. Br Med J 1972;1(801):685.
- Schmidt T, Wijga A, et al. Changes in cardiovascular risk factors and hormones during a comprehensive residential three month kriya yoga training and vegetarian nutrition. Acta Physiol Scan Suppl 1997;640:158-162.
- Shaffer HJ, LaSalvia TA, Stein JP. Comparing Hatha yoga with dynamic group psychotherapy for enhancing methadone maintenance treatment: a randomized clinical trial. Altern Ther Health Med 1997;3(4):57-66.
- Shannahoff-Khalsa DS, Ray LE, Levine S, et al. Randomized controlled trial of yogic meditation techniques for patients with obsessive-compulsive disorder. CNS Spectrums 1999;4(12):34-47.
- Singh V, Wisniewski A, Britton J, et al. Effect of yoga breathing exercises (pranayama) on airway reactivity in subjects with asthma. Lancet 1990;335:1381-1383.
- Sundar S, Agrawal SK, Singh VP, et al. Role of yoga in management of essential hypertension. Acta Cardiol 1984;39(3):203-208.
- Uma K, Nagendra HR, Nagarathna R, et al. The integrated approach of yoga: a therapeutic tool for mentally retarded children. A one-year controlled study. J Ment Defic Res 1989;33 ( Pt 5):415-421.
- Vedanthan PK, Kesavalu LN, Murthy KC, et al. Clinical study of yoga techniques in university students with asthma: a controlled study. Allergy Asthma Proc 1998;19(1):3-9.
- Vempati RP, Telles S. Yoga-based guided relaxation reduces sympathetic activity judged from baseline levels. Psychol Rep 2002;Apr, 90(2):487-494.
- Vyas R, Dikshit N. Effect of meditation on respiratory system, cardiovascular system and lipid profile. Indian J Physiol Pharmacol 2002;Oct, 46(4):487-491.
Last updated October 29, 2003
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