Private Practice Psychiatry
San Francisco, CA
November 26, 2004
Five
months ago I completed 24 years of school – 12 years of primary and secondary school,
then 4 years of university, followed by 4 years of medical school, and capped
off by 4 years of psychiatry residency.
I practiced yoga intermittently (once a month or so) during the past six
years. It was a recent two-month trip
to the Ashtanga Yoga Research Institute (AYRI) in Mysore, India that compelled
me to start thinking deeply about how practicing yoga can heal the brain, body,
and mind. Because of my long education in medicine and limited yoga practice,
I’m biased towards understanding yoga’s healing effects through the lens of
Western psychology and medicine. This
article is written from the perspective of a western scientist who is a novice
yoga practitioner.
There
is an accumulating body of scientific evidence documenting the many benefits of
yoga practice. On a physical level,
researchers have found that yoga practice can reduce symptoms and signs of
carpal tunnel syndrome[1], asthma[2]-[3], high blood pressure[4], osteoarthritis[5], heart disease (with a
net reduction in arterial plaques)[6]-[7], hyperglycemia and
diabetes[8], fibromyalgia[9], irritable bowel
syndrome[10], and physical fatigue
and tension[11]. Yoga may also reduce seizure frequency in
epileptics (there are conflicting reports)[12]-[13] and improve fatigue
symptoms in multiple sclerosis sufferers[14].
Physical
risks of yoga include hyper-flexion and over-extension of joints, resulting in
ligament and tendon sprains, strains, and tears, although there is no medical
literature available (and one recent New York Times article[15])
to support this. There are case studies
of vertebral and basilar artery tears in yoga students doing neck manipulations[16]-[17]. Similarly vertebral artery tears have been
reported due to various “activities [of] rapid head turning, tennis, yoga, and
vigorous exercise” in addition to volleyball and rollerblading[18].
On
the psychological level, yoga has been repeatedly shown to improve mood,
confidence, and attention. Several
surprising studies show that yoga has equal or greater effectiveness in
improving mood, confidence, and attention as aerobic exercises such as swimming
and dancing[19],[20],[21],[22]. Yoga, including a spirituality component,
has been shown to reduce stress, anxiety, depressive symptoms, and anger[23]. Because yoga is a form of moving meditation,
it may be inferred that meditation’s many physical and mental benefits also may
be obtained through yoga practice.
Please see my meditation article for a full
list of documented benefits.
From
my own experience and that of others I have spoken with, the mental benefits of
yoga also include reduced rumination, intellectualization, and distractability
as well as an increased sense of well-being, confidence, and clarity. On the emotional side, practitioners report
decreased impulsivity, irritability, lustfulness, and worry, and they feel
increased emotional stability, comfort with themselves, and patience. Physically the benefits are obvious (Madonna
is an excellent example) – improved muscle tone, strength, flexibility, and
skin radiance – and decreased weight (if one is overweight). Yoga won’t change your personality, but it
will reduce your reactivity to everyday irritations, disappointments, and
impulses.
From
conversations with other yogis and recent research (see endnotes), the signs
and symptoms of anxiety[24],
depression[25], attention-deficit
hyperactivity disorder (ADHD)[26],
addiction[27], and
obsessive-compulsive disorder (OCD)[28]
are reduced by regular yoga practice.
Additionally, one’s self-confidence and patience increase with a regular
practice. Yoga is prescribed for all
types of mental illness in India, and I suspect that it is a good treatment
even for mild psychoses. Naturally, one
has to be able to set aside the time and space to practice yoga everyday, and
for some people with severe mental illness, logistics and will-power may be
prohibitively difficult.
The
beneficial effects of yoga on mental health may be occurring through the
process of “neuroplasticity.”
Neuroplasticity refers to neurons’ tendency to change their structure
and function in order to adapt to the demands of new environments. For a pianist, the neurons coordinating and
controlling rapid finger movements will be more extensively networked than the
same neurons in the brain of a non-pianist.
This extensive neural networking occurs over time, due to practice and
concentrated use. People who do not
practice the piano will not have extensive networking of these neurons.
Similarly,
if one is practicing sustained attention on a daily basis, then it is probable
that the neurons that help us to sustain attention and resist impulses will be
strengthened. Scientists recently found
this to be the case with compassion.
Brain scans (functional MRI) of Tibetan monks who have practiced greater
than 10,000 hours of compassion meditation were compared with those from a
group of novice meditators. The monks’
brains showed greater activation in brain areas related to positive feelings
(left pre-frontal cortex) and less activation in areas associated with negative
emotions such as anxiety and anger (right pre-frontal cortex) than did the
novice meditators[29].
Additionally,
Tibetan monks showed greater gamma wave activity, associated with
consciousness, than novice meditators.
These gamma waves may be a measure for overall awareness. “That opens up the tantalizing possibility
that the brain, like the rest of the body, can be altered intentionally. Just
as aerobics sculpt the muscles, so mental training sculpts the gray matter in
ways scientists are only beginning to fathom. [30]” In the case of yoga, the sculpting is
through both physical and mental means.
Yoga
is the product of thousands of years of experiential research and philosophical
discourse by millions of practitioners.
The main precepts underlying yogic practice have been passed down both
verbally, physically, and textually from teacher to student since 1000
BCE. The major ashtanga yoga text is
the Yoga Sutra of Patanjali. According
to Patabbhi Jois – the founder of AYRI - it takes ten years of daily yoga practice
just to be ready to undertake teaching yoga.
Much of the learning is experiential and very subtle.
Reading
the yoga texts themselves can be a bit daunting. There are Sanskrit words scattered throughout in-depth
commentaries on somewhat arcane philosophical concepts. Yikes!
It’s not easy to figure out.
Naturally, some westerners have devised
simplifications of the basic messages of yoga theory, and these “Yoga
for Dummies”-type compilations make it much easier to understand. In the end we must learn through practice –
“Do your practice and all is coming,” Pattabhi Jois says. In that spirit, I’m going to comment on the
physical nature of yoga practice and how it affects one’s mind over time.
“At the heart of all meditative practices in Asia is what Indians call
yoga, the system that ‘yokes’ one’s consciousness to a spiritually liberating
discipline.[31]”
The
word “yoga” is derived from the same root as the word “yoke.” The word yoga is often interpreted as
meaning “union,” as in union of self with the eternal. “Yoga is the cessation of the turnings of
the mind[32].” “What turnings of the mind,” you may
wonder? As I understand this, it is
whenever you are caught up in trivialities or emotional dead-ends (greediness,
jealousy, desire, envy, anger, gluttony, self-righteousness, etc.) or thinking
the same types of thoughts over and over, without any resolution, your mind is
turning. The Buddhists call it “monkey
mind” – visualize the mind as a monkey running around, impulsive and
unproductive, to get the idea of its meaning.
Turnings
of the mind rarely lead to new or important insights. The mind is accustomed to babbling all day, typically twice as
often about negative (lack, wanting, anger, fear) than positive (wholeness,
love, joy, generosity) topics. Our
minds constantly engage in this babble as a protective mechanism. Yet in our modern world most of us are
geared up to face inconsequential or imaginary threats that are exaggerated (to
catch our attention) by media, politicians, advertisers, and other
salespeople. Rumination about what you
don’t have, your missed opportunities, perceived threats against you, or what
you want now can lead to feelings of depression and helplessness.
“The aim of yoga is to eliminate the control that material nature exerts
over the human spirit, to rediscover through introspective practice … a state
of perfect equilibrium and absolute spiritual calm, an interior refuge in the
chaos of worldly existence.[33]”
In
order to begin “yoking” the ceaseless turnings of the mind, we’ve got to have
some interest in or curiousity about practicing. Will-power is difficult to muster for anyone
who doesn’t prioritize an activity, and prioritization only comes about when we
deeply believe that the activity will be beneficial. Our deep motivating beliefs rarely come through cerebral means –
rarely from studying yoga philosophy.
Most of us are sold on evidence.
The belief in the benefits of yoga must come from somewhere, and in my
opinion it typically comes from role models.
We probably all know someone who is fit, confident, and fun to be around
who practices yoga. Yogis often project
an image of stability, balance, and peace-of-mind – traits that most of us are
seeking in our hectic daily lives.
Beginning
practice is easy, but continuing practice is quite difficult. Pushing through the soreness and fatigue can
be daunting for the beginning yoga student.
Naturally, we can be ambivalent about yoga, practicing one day and
skipping the next … and that’s OK! In
fact, wherever you are in your practice, it’s OK! That’s one of the principles of yoga, acceptance. We’ve got to be honest with where we are and
what’s going on with us. Do we really
want to prioritize yoga right now? Is
the practice worth it? Will you be
learning and growing doing something else?
A
wholesome, complete, and nonjudgmental assessment of our abilities is necessary
to begin yoga practice. For example, if
we don’t accept that our knees are tight, we may push them past their limits,
injuring ourselves and requiring a lengthy break from practice. Obviously, pain and injury are strict
disciplinarians. And if we can’t accept
our physical limitations - if we treat yoga like a competitive sport - then we
will soon injure ourselves and stifle further physical yoga practice.
Similarly,
we must accept that we are all ambivalent about yoga. Who really wants to wake up early every morning to spend an hour
straining and sweating and observing how our crazy minds work? If we’re perfectionists, then we may feel
pressured to achieve certain flexibility goals, and we will resent that our
bodies are not advancing as quickly as our ambitions. If we’re lazy, then we’ll resent having to prioritize attending
yoga classes. If we’re competitive or
have body issues, then we’ll spend a lot of time in class comparing ourselves,
which can be tortuous. All these things
happen, and they always will happen for us, and we need a heavy dose of courage
to get on the mat and face whatever comes up in these situations. Sometimes we ‘hit the wall’ and don’t feel
like doing yoga anymore, and that is exactly where we need to be. Through all this, the practice continues. “Practice, practice, practice…,” says
Pattabhi Jois.
I’ll
go briefly into yoga philosophy here.
There are “eight limbs” of ashtanga yoga, the yoga of Patanjali, and
only one of those limbs refers to the physical practice of the postures
(asanas). The other limbs guide us
towards proper conduct in daily life.
The eight limbs are guidelines for living the life of a yogi. The eight limbs (with no Sanskrit
references) are:
In
the same way that practicing a sport improves performance over time, the
practice of the eight limbs of yoga refines our physical, ethical, and
emotional lives.
So
how does yoga create these benefits?
Practice is the key to re-sculpting our grey matter, and the style of
practice determines the direction of neural reorganization. This reorganization occurs through the
mechanism of neuroplasticity.
I’ll
start at the beginning. Performing your
practice every day on schedule, rain or shine, good mood or bad, is a demonstration
of dedication and commitment. Making a
clear commitment, particularly to a long-term practice of self-development, is
the first step towards clearing away nagging self-doubts, inconsistency,
indecisiveness, and self-sabotage. The
regularity of the practice provides a daily ritual for centering the mind, and
when the practice is performed devotionally (such as for the healing of
humanity or dedicated to a higher power), it begins the internal cultivation of
faith.
When
we practice cultivating states of mind, such as gratitude and faith, we are
changing our physiological and emotional state. In order to begin deliberate cultivation of qualities such as
gratitude and faith, we must acknowledge that we have a choice. We have a choice to influence, as best we
can, how we create and experience our lives and feelings.
If
we see others with gratitude – for what they’ve taught us, shared with us, or
given us – then we ourselves will be filled with a sense of goodwill. That goodwill towards others is ultimately
reflected in our actions towards others.
Many spiritual practitioners and self-help gurus teach us to engage in
daily gratitude sessions where we remember and feel gratitude[35]. In ashtanga yoga the opening chant is said
in a tone of gratitude to all of the teachers who have passed down the practice
over time, so the day is begun in the spirit of gratitude. Gratitude is a trait intentionally
cultivated by many happy and successful people[36].
Faith
is also necessary to a full, satisfying life, as well as a remedy to
cynicism. The future is always
uncertain, and faith is the fuel that keeps us working towards something beyond
our immediate needs and desires. The
faithful believe that everything will work out as it should. Because of this deep belief, they often act
to ensure the best possible future for themselves and the world. In order to feel secure with ourselves and
our place in the world, it is helpful to feel faith that our activities are
meaningful.
Devotion
It
is easy to become attached to the physical and mental benefits of yoga. Practitioners may begin to see their
practice and their teachers with a possessive or exclusive affection. Teachers, such as Shankar Narayan Jois in
Mysore, advise that the entire asana practice be performed as a devotional
exercise. In this light we are not
performing yoga for the attainment of any goal, but as a demonstration of
long-term commitment to the mystery and divinity of the universe.
This
attitude of devotion is important for the cultivation of balanced mental
health. As with every other virtue,
devotion can be taken too far.
Devotion, as do gratitude and faith, breaks us out of a narrow focus on
our own interests. Yet extreme devotion
is occasionally used as a method of dissociating from and forgetting our
problems.
Mental
illnesses such as depression, OCD, anxiety, and some psychoses are
characterized by an excessive inward focus, in contrast to the outward foci of
faith, gratitude, and devotion.
Sufferers of these illnesses often believe that their past losses (in
the case of depression), future concerns (in the case of anxiety), safety
rituals (in the case of OCD), and overall personal significance (in the case of
some mild psychoses) are far more important to the rest of the world than they
actually are. This exaggerated sense of
self-importance is often remedied by a gradual surrender to that which is
greater than the individual (such as God, natural mystery, or the Divine). In yogic parlance, it is the reunion of the
individual self (Atman) with the universal soul (Brahman) through devotion that
releases us from the illusions of daily life (Samsara).
Service
and devotion in honor of something greater than oneself is fundamental to many
spiritual paths. Whether in devotion to
God with prayer, in service to community with charity works, or in service to
the ultimate good through waging war against evil, the focus of this type of
devotion is kept outside of the self.
This point is not to be taken lightly – sects within most of the world’s
major religions - such as Islam, Christianity, and Judaism - teach that
surrender to God is the path to peace.
The
duty of showing up for practice daily, regardless of circumstances, is one way
of making space for the self in the midst of the chaos of everyday living. Additionally, the practice of Mysore-style
ashtanga is typically self-led, and practitioners must be responsible to
themselves and their practice to keep up the rigorous schedule. In this way, the practice teaches
self-discipline and enhances one’s sense of personal responsibility.
Breath-control
(the fourth limb of yoga) involves even, measured inhalation and exhalation
through the nose during the entire yoga practice. Each breath, inhale or exhale, corresponds with one defined
position or movement. This
breath-control can be very difficult to hold during the more strenuous portions
of the practice, as the desire to breathe quickly due to oxygen deprivation
almost overwhelms the ability to remain steady and even.
Paradoxically,
practicing breath control actually enhances relaxation later. When we are smoothly inhaling and exhaling
as our bodies are urging us to breathe more oxygen, we are training our minds
to have control over feelings of panic and anxiety. We teach ourselves that a racing heart and shortness of breath
are all under our control. For
sufferers of panic disorder, the practice of yogic breath control may be one of
the most effective treatments, in my opinion.
Deep-breathing
into the belly, performed with regular inhale and exhale counts of “1, 2, 3 …
3, 2, 1…”, is an excellent treatment for acute panic and anxiety. I’ve successfully taught deep-breathing
techniques to many patients with anxiety disorders. Ironically, ashtanga yoga requires practitioners to breathe in a
manner that I consider anxiety-inducing throughout most of the
practice.
“Ujayi”
breathing refers to the exercise of holding the throat slightly closed during
yoga practice. This slight constriction
of the throat results in the “darth-vader”-style breathing heard in yoga shalas
during practice. Ujayi breathing
produces shortness of breath for beginners during strenuous portions of the
practice. Additionally, Ujayi breathing
creates resistance during inhalation and exhalation, opening and aerating the
lungs during exhalation, while strengthening the respiratory musculature during
inhalation.
Ujayi
breathing is performed along with a muscular contraction (muscular lock) of the
abdomen called “uddiyana bandha.”
Udianyna bandha refers to the sustained contraction of the muscles of
the abdomen, lifting up and in. Holding
in the belly (uddiyana bandha) makes it very difficult to breathe deeply, and
one definitely can’t breathe deeply into the abdomen.
The
Ujayi and uddiyana bandha practices are the virtually the opposite of what
anxious patients are taught in order to reduce their mental anxiety. From the perspective of western medicine,
the therapeutic mechanism of Ujayi breathing and uddiyana bandha may be through
a kind of behavioral conditioning. That
is, beginning ashtanga yoga practitioners are frequently exposed to
anxiety-inducing moments of chest-breathing and oxygen-hunger, wondering “how can
I get enough air … I’m going to explode!”
This repetitive exposure to a stressful situation conditions the
practitioner to other physiologically stressful situations.
Yoga
practitioners who are breathing smoothly and shallowly though their noses, while
simultaneously experiencing a racing heart and air-hunger, are training their
bodies and minds to react smoothly and calmly when they are in a similar
physiologic state in another context.
For example, a non-yogi who is terrified of public speaking, and who has
no practice with controlling racing thoughts and shortness of breath before a
speech, is likely to perform poorly when compared to a similarly terrified
speaker who is a yogi. The yogi has
successful experience working through these same feelings in yoga practice.
One
of the more odd aspects of ashtanga yoga practice, for new yogis, is holding
“mula bandha”. Mula banda refers to
sustained contraction of the muscles of the perineum and external anus. Holding both mula bandha and udianya bandha
and performing Ujayi breathing is done throughout practice. These three exercises provide three points
of focus for the mind. And just as the
body in athletics, the mind can be excercised to improve its performance. In this case, the mind is being excercised
to improve its ability to focus.
Other
mechanisms of mental focus include the maintenance of visual focus on certain
points throughout the practice. Instead
of looking around the yoga shala at teachers or neighboring practitioners, the
eyes are kept trained on one of three points, depending on the pose or movement
being performed. The three points of
focus are not solely visual - they also focus mental attention. The points of focus are the tip of the nose,
the belly button, and the tip of the fingers.
I’ve
outlined some of the mental and physical benefits of yoga above. I wish you an excellent journey, however it
leads you. “Practice, and all is
coming.”
[1] Marian S. Garfinkel; Atul Singhal;
Warren A. Katz; David A. Allan; Rosemary Reshetar; H. Ralph Schumacher,
Jr. Yoga-Based Intervention for
Carpal Tunnel Syndrome: A Randomized Trial.
JAMA 1998 280: 1601-1603.
[2] Singh V,
Wisniewski A, Britton J, Tattersfield A.
Effect of yoga breathing exercises (pranayama) on airway reactivity
in subjects with asthma. Lancet.
1990 Jun 9;335(8702):1381-3.
[3] Vedanthan PK, Kesavalu LN, Murthy KC, Duvall K,
Hall MJ, Baker S, Nagarathna S. Clinical study of yoga
techniques in university students with asthma: a controlled study. Allergy
Asthma Proc. 1998 Jan-Feb;19(1):3-9.
[4] Patel C, North WR. Randomised controlled trial of yoga and bio-feedback in
management of hypertension. Lancet.
1975 Jul 19;2(7925):93-5.
[5] Garfinkel MS, Schumacher HR Jr, Husain A, Levy M,
Reshetar RA. Evaluation of a yoga
based regimen for treatment of osteoarthritis of the hands. J
Rheumatol. 1994 Dec;21(12):2341-3.
[6] Manchanda SC, Narang R, Reddy KS, Sachdeva U,
Prabhakaran D, Dharmanand S, Rajani M, Bijlani R. Retardation of coronary atherosclerosis with yoga lifestyle
intervention. J Assoc Physicians India. 2000 Jul;48(7):687-94.
[7] Bharshankar JR, Bharshankar RN, Deshpande VN,
Kaore SB, Gosavi GB. Effect of yoga on
cardiovascular system in subjects above 40 years. Indian J Physiol
Pharmacol. 2003 Apr;47(2):202-6.
[8] Jain SC,
Uppal A, Bhatnagar SO, Talukdar B. A study of response
pattern of non-insulin dependent diabetics to yoga therapy. Diabetes
Res Clin Pract. 1993 Jan;19(1):69-74
[9] Michael
Doherty, Adrian
Jones. ABC of
Rheumatology: FIBROMYALGIA SYNDROME. BMJ
1995;310:386-389 (11 February).
[10] Taneja
I, Deepak KK, Poojary G, Acharya IN, Pandey RM, Sharma MP. Yogic versus conventional treatment in
diarrhea-predominant irritable bowel syndrome: a randomized control study. Appl
Psychophysiol Biofeedback. 2004 Mar;29(1):19-33.
[11] Berger BG,
Owen DR. Mood alteration with yoga
and swimming: aerobic exercise may not be necessary. Percept Mot Skills. 1992 Dec;75(3 Pt 2):1331-43.
[12] Panjwani U, Selvamurthy W, Singh SH, Gupta HL,
Thakur L, Rai UC. Effect of Sahaja yoga
practice on seizure control & EEG changes in patients of epilepsy. Indian
J Med Res. 1996 Mar;103:165-72.
[13] Ramaratnam
S, Sridharan K. Yoga for epilepsy. Cochrane
Database Syst Rev. 2000;(2):CD001524.
[14] Oken BS, Kishiyama S, Zajdel D, Bourdette D,
Carlsen J, Haas M, Hugos C, Kraemer DF, Lawrence J, Mass M. Randomized controlled trial of yoga and exercise in
multiple sclerosis. Neurology. 2004 Jun 8;62(11):2058-64.
[15] August 11, 2002, Sunday. LESLIE KAMINOFF; WRITTEN WITH COELI CARR. MY JOB; Mr.
Fix It for Injured Yoga Enthusiasts. MONEY AND BUSINESS/FINANCIAL
DESK. Late Edition - Final , Section 3 , Page 13 , Column
1.
[17] Fong KY,
Cheung RT, Yu YL, Lai CW, Chang CM. Basilar artery occlusion
following yoga exercise: a case report.
Clin Exp Neurol.
1993;30:104-9.
[18] DeBehnke
DJ, Brady W. Vertebral artery
dissection due to minor neck trauma. J Emerg Med. 1994 Jan-Feb;12(1):27-31.
[19] Netz Y, Lidor R. Mood alterations in mindful versus aerobic exercise modes. J
Psychol. 2003 Sep;137(5):405-19.
[20] Woolery A, Myers H, Sternlieb B, Zeltzer L. A yoga intervention for young adults with elevated
symptoms of depression. Altern Ther Health Med. 2004 Mar-Apr;10(2):60-3.
[21] Harinath K, Malhotra AS, Pal K, Prasad R, Kumar R,
Kain TC, Rai L, Sawhney RC. Effects of Hatha yoga and
Omkar meditation on cardiorespiratory performance, psychologic profile, and
melatonin secretion. J Altern Complement Med. 2004 Apr;10(2):261-8.
[22] Berger BG,
Owen DR. Mood alteration with yoga
and swimming: aerobic exercise may not be necessary. Percept Mot Skills. 1992 Dec;75(3 Pt 2):1331-43.
[23] Kennedy
JE, Abbott RA, Rosenberg BS. Changes in spirituality
and well-being in a retreat program for cardiac patients. Altern
Ther Health Med. 2002 Jul-Aug;8(4):64-6, 68-70, 72-3
[24]
Shannahoff-Khalsa DS. An introduction to
Kundalini yoga meditation techniques that are specific for the treatment of
psychiatric disorders. J Altern Complement Med. 2004
Feb;10(1):91-101.
[25] Woolery A, Myers H, Sternlieb B, Zeltzer L. A yoga intervention for young adults with elevated
symptoms of depression. Altern Ther Health Med. 2004 Mar-Apr;10(2):60-3.
[26] Jensen PS, Kenny DT. The effects of yoga on the attention and behavior of boys with
Attention-Deficit/ hyperactivity Disorder (ADHD). J Atten Disord. 2004
May;7(4):205-16.
[27] Sharma K,
Shukla V. Rehabilitation of
drug-addicted persons: the experience of the Nav-Chetna Center in India. Bull
Narc. 1988;40(1):43-9.
[28]
Shannahoff-Khalsa DS. An introduction to
Kundalini yoga meditation techniques that are specific for the treatment of
psychiatric disorders. J Altern Complement Med. 2004
Feb;10(1):91-101.
[29] SHARON BEGLEY, “Scans of Monks' Brains Show Meditation Alters
Structure, Functioning” Wall Street Journal - SCIENCE JOURNAL. November 5, 2004.
[30] SHARON BEGLEY, “Scans of Monks' Brains Show Meditation Alters
Structure, Functioning” Wall Street Journal - SCIENCE JOURNAL. November 5, 2004.
[31] YOGA: Discipline of Freedom. The Yoga Sutra Attributed to Patanjali. Translated by Barbara Stoller Miller. Bantam, New York: 1998. pp. ix.
[32] YOGA:
Discipline of Freedom. The Yoga
Sutra Attributed to Patanjali.
Translated by Barbara Stoller Miller.
Bantam, New York: 1998. pp 1.
[33] YOGA: Discipline of Freedom. The Yoga Sutra Attributed to Patanjali. Translated by Barbara Stoller Miller. Bantam, New York: 1998. pp 1.
[34]
http://www.holistic-online.com/Yoga/hol_yoga_astanga-limbs.htm.
[35] http://www.beliefnet.com/story/53/story_5393_1.html.
[36] Hill, Napolean. Think and Grow Rich. Ballantine Books; Reissue edition (May 12, 1987)