Overview

Definition

Yoga, derived from the Sanskrit word meaning "union," is a philosophy that connects the body, breath, and mind to energize and balance the whole person. This mind-body therapy involves physical postures, breathing exercises, and meditation to improve overall well-being. Today, millions of Americans of all ages and fitness levels practice yoga regularly. Although yoga is a spiritual practice to many, the majority of Westerners who practice yoga do so as an exercise and fitness routine or to reduce stress.

History of yoga

While the practice of yoga started nearly 6,000 years ago, the earliest written records documenting yoga as a health practice are recorded in The Vedas, sacred texts from India dating back at least 3,000 years. Other ancient texts have documented the philosophy and teachings of yoga as well. However, yoga did not emerge as a fully developed practice until 500 B.C. In its traditional form, yoga is considered a complete lifestyle that provides a path to spiritual enlightenment.

The dimensions of yoga are sometimes depicted as a tree with eight limbs:

• Pranayama (breathing)
• Asana (postures)
• Yama (restraint)
• Niyama (healthy observances)
• Pratyahara (sensory withdrawal)
• Dharana (concentration)
• Dhyana (meditation)
• Samadhi (higher consciousness)

The practice of yoga came to the United States in the 1890s as a result of the teachings of a guru named Swami Vivekananda. It gained popularity in the 1960s because of a rising interest in and cultural acceptance of alternative modalities and mind-body therapies. Today, yoga is often practiced as an exercise form separated from its traditional spiritual roots. In this form, yoga exercise is taught at local YMCAs, health clubs, and yoga centers, and is often part of disease prevention and management programs in hospitals, such as stress-reduction courses for people with high blood pressures and heart disease.

Types of yoga

As the different connections between the mind and body were explored, various branches or paths of yoga developed. These include:

• Bhakti Yoga --This form of yoga aims to take all of the love in one's heart and direct it toward the divine. By seeing God in all of creation, the person who practices regularly becomes filled with respect for all life and is encouraged to be sacrificial and to treat others generously.
• Hatha Yoga -- This the most commonly practiced form of yoga in the United States today. Emphasis is placed on physical postures or exercises, known as asanas, with the goal of balancing the opposites in one's life. During Hatha yoga sessions, flexing is followed by extension, a rounded back is followed by an arched back, and physical exercises are followed by mental meditations.
• Jnana Yoga -- This form of yoga emphasizes deep contemplation. Practitioners seek Jnana, or "wisdom," through meditation. The goal is to be one with God.
• Karma Yoga -- This form of yoga is based on the philosophy that "yesterday's actions determine today's circumstances." Practitioners of Karma yoga make a conscious decision to perform selfless acts of kindness. By making today's actions positive, they hope they can improve tomorrow's circumstances for both themselves and others.
• Raja Yoga -- This form is known in India as "the royal (raj) road to reintegration." The goal of this type of yoga is to blend the four layers of self: the body, the individual consciousness, the individual subconsciousness, and the universal and infinite consciousness. Raja yoga, being most concerned with the mind and spirit, places its emphasis on meditation.
• Tantra Yoga -- Like Hatha yoga, practitioners of Tantra yoga seek to balance the opposites in their lives. They also try to break free of the "six enemies" (physical longing, anger, greed, vanity, obsession, jealousy) and the "eight fetters" (hatred, apprehension, fear, shyness, hypocrisy, pride of ancestry, vanity of culture, egotism) by using discipline, training, and rituals.

Hatha yoga, the style most Americans practice, is often a general term used to describe many different types or styles of yoga. If a class is simply termed "Hatha yoga," it will probably be relatively gentle and include both breathing and physical exercises (postures). Other styles of yoga can be more intense. Among the more popular styles of yoga are:

• Ashtanga or Power yoga -- a more physically demanding workout involving constant movement from one posture to another ("flow").
• Bikram, or Hot, yoga -- a series of 26 asanas (postures) practiced in a room that is 95 to 100 degrees in order to warm and stretch the muscles, ligaments, and tendons, and to purify the body through sweat.
• Integral -- a gentle type of yoga that may include breathing exercises, chanting, and meditation.
• Iyengar -- emphasizes great attention to detail and precise alignment, and holding poses for long periods of time.
• Kundalini -- emphasizes the effects of breath on the postures, with the aim of freeing energy in the lower body to move upwards.
• Viniyoga -- adapts postures to each person's needs and abilities, and synchronizes breath and postures (breath leads the body into each posture).

How yoga works

Scientists don't know exactly how yoga produces its healthful effects. Some say it works like other mind-body therapies to reduce stress, and others believe that yoga promotes the release of endorphins (natural painkillers and mood elevators) from the brain. Studies show yoga can lower heart rate and blood pressure, increase muscle relaxation, and increase breathing capacity.

All branches of yoga mentioned in this report incorporate three major techniques: breathing, exercise (asana or postures), and meditation. These three techniques have been shown to improve health in many ways:

• Breathing lessons -- in yoga, breathwork is known as pranayama. Pranayama increases blood circulation and reduces oxygen consumption, which brings more oxygen to the brain, and improves the efficiency of oxygen use in the body. Also, as lung tissue becomes more elastic and the surrounding muscle more flexible, the practice of pranayama can also increase lung capacity. Getting ample air into our lungs helps us feel alert and focused.
• Asanas (postures) -- provide a gentle-to-intense workout that enhances strength, flexibility, and balance. Some asanas are designed to massage the internal organs, improve circulation, hormone function, digestion, and other body processes.
• Meditation -- stills the mind and induces both physical and emotional relaxation. In so doing, it reduces blood pressure, chronic pain, anxiety, and cholesterol levels.

A typical yoga session

Although most people learn yoga by taking a group class with an experienced instructor, one-to-one sessions with certain practitioners are available. Such private, or semi-private, sessions are more expensive. Classes usually last from 45 - 90 minutes and begin with warm-up exercises, proceed to a guided series of yoga postures designed to stretch and tone all areas of the body, and generally end with deep relaxation or meditation. Throughout the class, the teacher instructs you on breath control and proper body alignment.

Classes are generally taken once a week (or more, if desired). Your instructor will likely encourage you to practice at home to get the most from yoga.

The benefits of yoga

Yoga improves fitness, lowers blood pressure, promotes relaxation and self-confidence, and reduces stress and anxiety. People who practice yoga tend to have good coordination, posture, flexibility, range of motion, concentration, sleep habits, and digestion. Yoga is a complementary therapy that has been used with conventional therapies to help treat a wide range of health problems, but it is not a cure for any particular disease.

Studies show that yoga may help the following conditions:

• Anxiety and stress
• Arthritis (osteoarthritis and rheumatoid arthritis)
• Asthma
• Cancer (as an adjunct therapy to reduce stress and strengthen the immune system)
• Chronic back pain
• Diabetes
• Heart disease, by lowering cholesterol levels, lowering blood pressure, lessening stress, and reducing the frequency and severity of chest pain (when combined with a healthy diet)
• High blood pressure
• Hormonal imbalances
• Irritable bowel syndrome
• Pregnancy

In addition, yoga postures aimed at stretching and strengthening the joints in the upper body may improve grip strength and diminish pain among people with carpal tunnel syndrome.

Precautions

Some people may experience stiffness as their bodies adapt to different postures. In addition, as with any physical activity, yoga may lead to an injury if not practiced properly. This is why practicing yoga under the guidance of a trained professional is important.

Be sure to check with your doctor before trying yoga if you have high blood pressure, heart disease, arthritis, or a recent back injury, as you would any physical activity. In addition, if you have any of these conditions, choose one of the gentler forms of yoga discussed earlier.

Some postures are not recommended during pregnancy, but special classes are available for pregnant women. Some postures should not be practiced during menstruation. Be sure to contact your doctor if any exercises cause headaches, muscle cramps, dizziness, or severe pain in your back, legs, or joints.

Remember that yoga instructors are not doctors. Only you and your doctor can decide if a certain yoga posture is too strenuous or might cause you injury depending on your condition.

Resources

International Association of Yoga Therapists (IAYT) -- www.iayt.org

Yoga Alliance -- www.yogaalliance.org

Yoga Journal -- www.yogajournal.com

Supporting Research

Anand MP. Non-pharmacological management of essential hypertension. J Indian Med Assoc. 1999;97(6):220-225.

Apte NK, Kabekar VG. Prevention of E.N.T. diseases. Indian J Med Sci. 1998;52(9):383-394.

Berk B. Yoga for moms. Building core stability before, during and after pregnancy. Midwifery Today Int Midwife. 2001;(59):27-29.

Bharshankar JR, Bharshankar RN, Deshpande VN, et al. Effect of yoga on cardiovascular system in subjects about 40 years. Indian J Physiol Pharmacol. 2003;Apr, 47(2):202-206.

Bijlani RL, Vempati RP, Yadav RK, et al. A brief but comprehensive lifestyle education program based on yoga reduces risk factors for cardiovascular disease and diabetes mellitus. J Altern Complement Med. 2005;Apr, 11(2): 267-274.

Birkel DA, Edgren L. Hatha yoga: improved vital capacity of college students. Altern Ther Health Med. 2000;6(6):55-63.

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.

Ernst E. Breathing techniques -- adjunctive treatment modalities for asthma? A systematic review. Eur Respir J. 2000;15(5):969-972.

Galantino ML, Bzdewka TM, Eissler-Russo JL, et al. The impact of modified Hatha yoga on chronic low back pain: a pilot study. Altern Ther Health Med. 2004;Mar-Apr, 10(2):56-59.

Garfinkel MS, Singhal A, Katz WA, Allan DA, Reshetar R, Schumacher HR Jr. Yoga-based intervention for carpal tunnel syndrome: a randomized trial. JAMA. 1998;280(18):1601-1603.

Harte JL, Eifert GH, Smith R. The effects of running and meditation on beta-endorphin, corticotropin-releasing hormone and cortisol in plasma, and on mood. Biol Psychol. 1995;40(3):251-265.

Jorm AF, Christensen H, Griffiths KM, Rodgers B. Effectiveness of complementary and self-help treatments for depression. Med J Aust. 2002;176 Suppl:S84-96.

Kreitzer MJ, Snyder M. Healing the heart: integrating complementary therapies and healing practices into the care of cardiovascular patients. Prog Cardiovasc Nurs. 2002;17(2):73-80.

Labarthe D, Ayala C. Nondrug interventions in hypertension prevention and control. Cardiol Clin. 2002;20(2):249-263.

La Forge R. Mind-body fitness: encouraging prospects for primary and secondary prevention. J Cardiovascular Nurs. 1997;11(3):53-65.

Luskin FM, Newell KA, Griffith M et al. A review of mind/body therapies in the treatment of cardiovascular disease. Part 1: Implications for the elderly. Altern TherHealth Med. 1998;4:46-61.

Luskin FM, Newell KA, Griffith M et al. A review of mind/body therapies in the treatment of musculoskeletal disorders with implications for the elderly. Altern TherHealth Med. 2000;6(2):45-56.

Mahajan AS, Reddy KS, Sachdeva U. Lipid profile of coronary risk subjects following yogic lifestyle intervention. Indian Heart J. 1999;51(1):37-40.

Malathi A, Damodaran A. Stress due to exams in medical students -- role of yoga. Indian J Physiol Pharmacol. 1999;43(2):218-224.

Manjunath NK, Telles S. Improved performance in the Tower of London test following yoga. Indian J Physiol Pharmacol. 2001;45(3):351-354.

Manocha R, Marks GB, Kenchington P, Peters D, Salome CM. Sahaja yoga in the management of moderate to severe asthma: a randomised controlled trial. Thorax. 2002;57(2):110-115.

Miller JJ, Fletcher K, Kabat-Zinn J. Three-year follow-up and clinical implications of a mindfulness meditation-based stress reduction intervention in the treatment of anxiety disorders. Gen Hosp Psychiatry. 1995;17(3):192-200.

Miller AL. The etiologies, pathophysiology, and alternative/complementary treatment of asthma. Altern Med Rev. 2001;6(1):20-47.

Ott MJ. Yoga as a clinical intervention. Adv Nurse Pract. 2002;10(1):81-3, 90.

Pandya DP, Vyas VH, Vyas SH. Mind-body therapy in the management and prevention of coronary disease. Compr Ther. 1999;25(5):283-293.

Pettinati PM. Meditation, yoga, and guided imagery. Nurs Clin North Am. 2001;36(1):47-56.

Quigley D, Dean CFA. Yoga. In: Novey DW, ed. Clinician's Complete Reference to Complementary and Alternative Medicine. St. Louis, Mo: Mosby; 2000:141-151.

Ray US, Mukhopadhyaya S, Purkayastha SS, et al. Effect of yogic exercises on physical and mental health of young fellowship course trainees.Indian J Physiol Pharmacol. 2001;45(1):37-53.

Sahay BK, Sahay RK. Lifestyle modification in management of diabetes mellitus. J Indian Med Assoc. 2002 Mar;100(3):178-80

Sathyaprabha TN, Murthy H, Murthy BT.Efficacy of naturopathy and yoga in bronchial asthma--a self controlled matched scientific study. Indian J Physiol Pharmacol. 2001;45(1):80-86.

Silverberg DS. Non-pharmacological treatment of hypertension. [review] J Hypertens Suppl. 1990 Sep;8(4):S21-26.

Spicuzza L, Gabutti A, Porta C, Montano N, Bernardi L. Yoga and chemoreflex response to hypoxia and hypercapnia. Lancet. 2000;356(9240):1495-1496.

Steurer-Stey C, Russi EW, Steurer J. Complementary and alternative medicine in asthma: do they work? Swiss Med Wkly. 2002;132(25-26):338-344.