1. The Physiological Effects of Breathing
THE PHYSIOLOGICAL EFFECTS OF PRANAYAMA
by Aoife Brennan
Pranayama is a sanskrit word composed of the words ‘prana’ meaning vital life-
force and “ayama” meaning restraint. The word pranayama thus translates as the regu-
lation or control of life-force. The word prana has been trans-
lated as many things including air, breath, spirit, life-force, en-
ergy, subtle energy, vital energy, soul and principle of life, all es-
sentially trying to convey the all-pervasiveness and vastness of
the life-sustaining energy of the universe which the word prana
represents (Apte, 1965). Prana is a concept central to the prac-
tices of yoga where it is believed to flow through channels in
the body called nadis. In relation to yogic practices pranayama
Fig 1. A drawing from an an-
is usually translated more directly as breath control (Feuer-
cient parchment showing the
stein, 1998). An alternative root of the word is given by Rama- main nadis of the body. The
artist has drawn some outside
murti Mishra who says that “Expansion of individual energy the body for purpose of clarity
but they are all located within
into cosmic energy is called pranayama” which gives a deeper the body
insight into the purpose of pranayama to a yoga practitioner.
Pranayama channels the prana in the body to calm, rejuvenate and uplift the mind. It
serves as an important bridge between the external, active and highly physical practice
of yoga asana and the subtle internal practices that lead the yogi into deeper states of
The ancient practice of yoga was composed into a darshan (philosophy) by Patan-
jali in his book Patanjali Yoga Sutra. In this book he formulated yoga as an eight-
limbed path, of which pranayama is the fourth limb. Chapter 2, sutra 49 describe
pranayama as “Tasmin sati svasaprasvasayor-gitivicchedah pranayamah”, “Regulation of
2. The Physiological Effects of Breathing
breath or the control of prana is the stoppage of inhalation and exhalation, which fol-
lows after securing that steadiness of posture or seat” (Yoga Sutras, 2:49). Here, Patan-
jali is stating that only those that have mastered their physical
body through asana, such that they can comfortably sit for long
periods of time, can progress to practicing pranayama. As a
consequence, there are differences of opinion between the
major yoga traditions on when a student should be introduced
to the practice of pranayama. In the integral yoga tradition
propounded by Swami Satchidananda, pranayama is incorpo-
rated into every yoga class. A typical session starts with asana,
moves on to pranayama and ends with seated meditation but
Fig 2. A representation of only at advanced levels are techniques such as breath reten-
Patangali. Hindu tradition
states that when all the mu- tion (Kunbacha) or the chin lock (jalandhara bandha) intro-
nis and rishis approached
Lord Vishnu for a means to duced. In Ashtanga ujjayi breathing is taught alongside mula
cure illness (physical, mental
and emotional) he gave them bandha (root lock) and uddiyana bandha (abdominal lock).
the serpent Adishesha with
1,000 heads (the symbol of These concepts are introduced to beginners and carried along
awarness) who took birth in
the world as Maharishi
and developed in conjunction with the asana practice. The
practitioner is guided to some degree in this but, like that as-
ana practice, the ujjayi breath develops with yoga practice and a deeper understanding
of the asana. Seated pranayamas are also taught as part of this tradition but usually
only after a practice of three to five years and the mastering of at least the primary se-
ries of asanas. There are six different pranayamas taught as a series and each one is
built on the previous technique and are practiced with the eyes open (Cummins, Yoga
Journal). Iyengar yoga, like ashtanga, only introduces separate pranayama practices after
a students has a strong asana practice but no specific breathing technique is not taught
to beginners in conjunction with the asana. Ujjayi breath is taught but only as a sepa-
3. The Physiological Effects of Breathing
rate practice after the yogi has first been guided through a supine breath awareness
practice which is done lying down with the chest and head supported to allow com-
plete focus on the breath and very precise directions are given to develop breathing
The Physiology of Breathing and Respiration
The lungs by themselves are immobile, sponge-like organs consisting of a microfine
network of tiny air-sacks called alveoli. The alveoli
sit at the end of a series of branch like tubules that
spread out from the trachea (windpipe) in the chest.
The lungs are encased in a the thoracic cavity
which is formed by the ribs, spine, diaphragm and
an array of muscles both big and small. It is the
concerted action of the muscles that brings about
Fig 3. Structure and blood supply
the process of breathing. Unlike many other inter- of the alveoli of the lungs
nal processes of the body, such as pumping blood
and moving of food through the digestive system, breathing results from semi-
conscious and habitual contraction of muscles that can be
brought to conscious awareness if desired. It is the cultivation of
this awareness that is the foundation of all pranayama practices
and it is the choice of muscles that we choose to move the lungs
that determines the type of breath we take. At the end of a nor-
mal exhale, the thoracic cavity is at equal pressure with the out-
side of the body. The contraction of the diaphragm and/or other
Fig 4. The thoracic cavity is
encased in the ribs, dia- muscles of the thoracic cavity increases the space in the cavity
phragm and surrounding
4. The Physiological Effects of Breathing
and therefore decreases the pressure causing
air to rush into the lungs from outside. When
these muscles relax, space in the cavity de-
creases causing the pressure to increase. This
forces the air out of the lungs until the pres-
sure is yet again equal with that of the exter-
nal environment (Fig 4.). Therefore, in normal
breathing, inhalation is active as muscle con-
traction is required and exhalation is passive
Fig 5. The role of the diaphragm in chang-
as no energetic input is needed. ing the pressure in the lungs in breathing.
On a cellular level, breathing is the body’s way of absorbing oxygen and excreting
the carbon dioxide (CO2) produced by the body when sugars are metabolised to pro-
duce energy. The body is capable of detecting oxygen levels in the blood but the pri-
mary determinant of the breathing urge is CO2 levels. These levels can profoundly af-
fect the physical and mental states of the body in many ways. CO2 is a primary regula-
tor of the acid-alkaline balance of the body which determines the rate of activity of
other biochemical processes. Breathing that is too slow or shallow can cause respira-
tory acidosis (acidic blood) resulting in headaches, confusion and anxiety.
Rapid shallow breathing patterns are often associated with people living with
stress where the depleted oxygen levels aggravate the mind further in a vicious cycle.
This is largely due to the fact that, unlike the other organs, the brain need a constant
oxygen supply in order to maintain it’s functional and structural integrity. Long-term
rapid shallow breathing (often caused by poor posture or weak muscles) can result in
the rib cage and surrounding muscles becoming stiff causing inhalation to become
more difficult and deeper breathing almost impossible. Less elasticity and weak mus-
5. The Physiological Effects of Breathing
cles leave stale air in the tissues of the lungs, preventing fresh oxygen from reaching
the blood stream. The resultant poor oxygen supply can cause respiratory disease, de-
crease mental alertness, sluggishness
or heart disease.
Rapid deep breathing, or hy-
perventilation, is usually caused by
anxiety and causes low blood CO2
levels. This shifts the body’s pH to-
wards alkaline, weakening the im-
mune system. CO2 helps dilate
Fig 6. The anatomy of an asthma attack. smooth muscle tissue and insufficient
CO2 can cause spasms throughout the
body including the brain and bronchi.. Good examples are the spasms that take place
during asthma attacks and migraines. Therefore, it is evident that the quality and depth
of the breath can have profound and varying physiological effects on both the body
The Consequences of Breath Regulation
Too much CO2 and not enough oxygen creates sluggishness and depression and
can contribute to anxiety and panic attacks. Long, deep inhales raise oxygen levels to
rebalance the blood oxygen levels. Examples of pranayama techniques that involve ex-
tended inhalation include ujjayi breathing and the yogic breath.
Too much oxygen and not enough CO2 can create an agitated state. Controlled,
long exhales conserve CO2 , rebalances the system and ensures the complete elimina-
6. The Physiological Effects of Breathing
tion of toxins that can build up with inefficient exhalation. Examples of pranayamas
involving extended exhales include viloma and brahmari breath.
Breath retention or “kumbhaka” takes two forms in pranayama. Holding the
breath in (antara kumbhaka) and holding the breath out (bahya kumbhaka). This prac-
tice increases heat in the body, improves concentration as mental activity is restricted
and increases lung capacity.
Regardless of the pranayama technique employed pranayama should always follow
some basic principles:
Breathing exercises should never be pushed to the point of weariness or exhaustion.
Exercises should not be repeated too often.
They should not be merely mechanical.
There should be no hurry or haste.
Attention should be concentrated on the exercise while it is being performed.
There should always be variety and change in the exercises.
Exercise should always be gentle and nonviolent.
Breathing should not be jerky or irregular, but smooth, steady and continuous.
A selection of pranayama techniques and their physiological effects
Abdominal or ‘diaphragmatic” breathing consists mainly of breathing deep down into
the abdomen by changing the position of the diaphragm. When you inhale the dia-
phragm gently descends into the abdomen pushing the stomach forward with no strain.
When exhaling you gently allow the stomach to return to its normal position. We often
use this low breathing when we are sleeping or hunched forward. Conscious diaphrag-
7. The Physiological Effects of Breathing
matic breathing is extremely relaxing to the autonomic nervous system (ANS) which is
essential preparation for deep meditation. The ANS controls
heart rate, digestion, respiration rate perspiration and diame-
tre of the pupils. With this breathing more air is taken into
the lungs than in chest breathing as the lower lobes of the
lungs are larger that the upper lobes. The abdominal organs
are also massaged by the movements of the diaphragm and
the celiac (solar) plexus never centre is stimulated. Abdomi-
nal breathing has been shown to improve quality of life in
breast cancer patients after a mastectomy (Kim et al., 2005), Fig 7. Abdominal breathing
reduce the occurrence of non-sleep bruxism (Ando and Sa-
kurai, 2006) and relieve anxiety of women diagnosed with preterm labour (Shim and
Chang,, 2006). Abdominal breathing, combined with the rhythmical pumping of the dia-
phragm helps turn on the parasympathetic nervous system - our “rest and relax” re-
Dirgha pranayama or “yogic breath’
Also know as the three-part breath, dirgha pranayama is done seated and involves taking
a full breath in three separate inhalations, each with a short pause between them; the
ﬁrst deeply into the abdomen as far as the rib cage, the second into the rib cage expand-
ing the ribs and ﬁnally all the way up to the chest and clavicles which actually lift slightly
as the lungs ﬁll with air. The exhale is also done in three parts but in the opposite direc-
tion, clavicles descending ﬁrst, then ribs and abdomen, again each with a short pause in
between. This is a slow deep breath that utilises all the alveoli in the lungs, ﬂushing the
entire lungs with fresh air and allowing for greater percentage of oxygen to be in hales
making oxygen/CO2 exchange more efﬁcient.
8. The Physiological Effects of Breathing
The ujjai breath (”victorious breath”) is best know for it’s use throughout the asana prac-
tice in Ashtanga yoga but it is a separate pryanayama technique in itself involving the
gently contraction and lifting of the uddiyana bandha and the mula bandha to lift the
breath up into the thoracic cavity. It can be practiced with or without kumbhakas. It is
also know as the ocean breath due to the sound made by the gentle engagement of the
jalandhara bandha in the throat to create some resistance to the passage of air. This
sound should become more subtle as the practitioner advances in both asana and
pranayama so that it is audible to only the practitioner themselves. In the yoga sutras
Patanjali suggests that the breath should be dirga (long) and suksma (smooth). It is a bal-
ancing and calming breath which build up internal heat and increases oxygenation
(Telles and Desiraju, 1991).
This pranayama is also known as alternate nostril breathing as the thumb of the right
hand is used to close the right nostril and the ring ﬁnger of the same hand is used to
close the left nostril. One round consists of inhaling
through one nostril for a deﬁned length of time (varying
from person-to-person) and exhaling for the same length
of time the same side. This nostril is then closed and the
same breath is repeated through the other nostril. In a
controlled study is was shown that breathing through the
Fig 8. Alternate nostril
right nostril resulted in a signiﬁcant increase of 37% in breathing
baseline oxygen consumption, alternately breathing
through both nostrils showed and 18% increase while breathing through the left nostril
resulted in a 24% increase. The left nostril pranayama group showed in increase in volar
galvanic skin resistance, the electrical resistance of the skin which is a measure of emo-
9. The Physiological Effects of Breathing
tions in people that is part of the polygraph test. Fear, anger, startle response, sexual feel-
ings are all among the emotions which may produce similar GSR responses. An increase
is interpreted as a reduction in sympathetic nervous system activity (Telles et al. 1994).
These results suggest that breathing selectively through either nostril could have a
marked activating effect or a relaxing effect on the sympathetic nervous system.
Viloma means against the natural order of things. In viloma pranayama, inhalation or ex-
halation is done with several pauses. It teaches the practitioner how to fully utilise the
entirety of the rib cage and how to direct the breath into speciﬁc areas of the chest en-
suring a deep breath. Viloma can also be practiced through alternate nostrils and is
called anuloma viloma. Viloma aerates the lungs and improves the muscle tone of the
breathing muscles. Both anuloma viloma and viloma have been said to lower blood pres-
sure, however the only controlled scientiﬁc study showed that there was an increase in
systolic blood pressure probably due to cutaneous vasoconstriction as shown by the si-
multaneous decrease in digit pulse volume (Telles et al., 1993). Both practices have also
been shown to increase oxygen consumption and therefore may be of beneﬁt to the
obese who are known to have a lowed resting metabolic rate than the non-obese (Dunani
et al., 1986).
Brahmari means bumble bee. In this breathing practice
your lips are shut, the ears and eyes closed with the ﬁn-
gers and you gently and smoothly make the sound like a Fig 9. Brahmari pranayama involves
humming like a bumble-bee to cre-
humming bee in your throat. The vibrations can be felt in ate vibrations.
the throat, jaws and face and can be done by anyone re-
gardless of age or ﬁtness level. At the moment there are not detailed scientiﬁc studies
10. The Physiological Effects of Breathing
conducted on brahmari pranayama alone but proposed beneﬁts include invigoration of
the thyroid gland increasing metabolism, curing migraine and triggering serotonin re-
lease resulting in balanced moods although altered serotonin levels has been implicated
in causing migraines so caution must be observed.
Sitali is also called tongue hissing due to the sound produced when practicing it. The
tongue is curled up into a tube and during inhalation the air passes over the moist
tongue, cooling down and refreshing the throat. The tongues is drawn back into the
mouth and the lips are closed at the end of the inhalation and the exhalation takes place
either through the throat or alternately through the nostrils. This is a cooling pranayama
which is though to have developed from observation of how animals breath to cool down
using their tongues.
Kapalabhati means skull shining breath and is one of the cleansing techniques of yoga. If
there is mucus in the air passages or tension and blockages in the chest it is often helpful
to breath quickly. In this practice the diaphragm and associated muscles are used to
“pump” the air rapidly out of the lungs in a forced exhalation. This is followed by a rapid
but passive inhalation. “Bhati” means “that which brings lightness”. One must be careful
with this technique because there is a danger of creating great tension with the breath or
one may become quite dizzy when breathing becomes rapid. For this reason kapalabhati
is usually concluded with some deep slow breaths. One study showed that kapalabhati
modiﬁes the autonomic status by increasing sympathetic activity (”ﬁght-or-ﬂight”) with
reduced vagal activity (Vagus nerve innervates the lungs and stomach, increases heart
rate and blood pressure) (Raghuraj et al., 1998).
11. The Physiological Effects of Breathing
Due to the semi-conscious nature of breathing we rarely observe our breath but
since out state of mind is reflected in the way we breath, it follows that by controlling
our breath we can learn to control out state of mind. A calm, peaceful mind is content
and non-violent and more receptive to the sense withdrawal (pratyahara) and deep
concentration (dharana) that bring about states of meditation. The health benefits are
scientifically proven with researchers reporting that pranayama is beneficial in treating
a range of stress related disorders (Brown et al., 2005), improving autonomic functions
(Howorka et al., 1995), relieving symptoms of asthma (Cooper et al., 2003; Vedanthan et
al., 1998), and reducing sigs of oxidative stress (Bhattacharya et al., 2004; Jerath et al.,
2006). Anecdotal evidence from practitioners report that the practice develops a steady
mind, strong will-power and sound judgment (Light on Pranayama, 6th ed.) and also
claim that sustained pranayama practice extends life and enhances perception (Asana
Pranayama Mudra Bandha, 2002). Will all the far-reaching benefits to the mind and
body, pranayama is something that cannot be ignored as part of a solid yoga practice
and should be practiced regularly by yogis of all ages and abilities.
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12. The Physiological Effects of Breathing
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