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The Biopsychology of Yoga

Frank Murphy - Highland Yoga Student

Yoga strikes me as a very humanistic approach to psychology.  It accepts people as they are, and attempts to get people to accept and love themselves.  What is it that brings about this attitude towards life that people who do not practice yoga may not be experiencing?  I will go over a few yoga poses and briefly describe their mental benefits.

The headstand is a very challenging pose for those who have spent most of their lives trying to avoid ending up with his/her head on the ground.  When the body is inverted, there is a rush of fresh, oxygenated blood to the brain.  According to Yoga: Mind and Body (1998) this pose increases memory, concentration, and intellectual capacity and enhances the sensory faculties as well.

The shoulder stand pose is done lying on the back.  The yogi lifts the feet straight into the air and balances all the weight on the shoulder blades.  The elbows are bent and hands support the back.  Yoga: Mind and Body advises that this pose relieves lethargy and mental sluggishness, as well as helps to cure insomnia and depression.

Many poses are done in sequence.  The pose which typically follows the shoulder stand is called the plow.  This pose is attained by reaching behind the head with the feet and bringing the toes to the floor as well as straightening out the arms.  This pose relieves insomnia and restless sleep, enhances physical and mental relaxation, and helps to develop mental poise and inner balance (Yoga: Mind and Body).

Yoga is about finding balance and harmony.  Many poses have counterposes.  The counterpose to plow is the fish.  One lies on his/her back and brings the elbows as close as possible under the body.  The yogi lifts the chest off the floor and arcs the neck back so the top of the head is on the floor with little weight on it.  (Yoga: Mind and Body ) This pose is good for its mood and emotion regulation, and for its stress and mental agitation relief.

Forward bending poses greatly enhance concentration and mental endurance, invigorate the mind and nervous system, and control many nervous complaints (Yoga: Mind and Body).  This simple pose is performed by sitting with an erect spine and stretching the legs straight in front of you with feet flexed back and quadriceps engaged.  Stretching the arms overhead, the yogi reaches for the toes with a straight back.

The cobra pose demands considerable concentration, and thus strengthens this faculty (Yoga: Mind and Body).  Lying face down on the floor the yogi brings the hands to the floor, palms face down, fingers below the shoulders.  With legs stretched straight back and feet pressing into the floor, the shoulders pinch the sides as the head looks up and stretches back.  This pose is held for 5 - 8 breaths.

In order to encourage concentration and perseverance a yogi might want to add the locust to their practice.  Lying face down with the arms drawn under the body and hands clinched together beneath the groin, the yogi stretches the chin toward the floor without touching it, shifts the body weight forward and raises the legs off the ground.  The goal is to get the feet as high as possible.

According to Yoga: Mind and Body, regularly practicing the bow develops internal balance and harmony, and strengthens concentration and mental determination.  This pose is found lying face down on the floor and drawing the ankles above the buttocks.  With the face on the floor, reach with both arms and grab the respective ankle.  Lift the head and chest off the floor as your raise your feet toward the ceiling finding a balance in the grip you have on your ankles.

Curing disorders of the nervous system and bringing peace of mind (Yoga: Mind and Body) spinal twists are also a great way to massage abdominal muscles and relieve digestive problems.  Sitting on your heels pull your right foot out from under you and place it on the outside of your left knee.  Your left foot should now be in front of your right buttock.  Place your right hand on the floor behind you and stretch the left arm overhead.  Bring the left arm down towards your right foot and twist towards your right with your head looking over your right shoulder.

The crow is a balancing pose which demands and greatly develops powers of concentration, nourishes mental awareness, encourages a feeling of inner balance, and prepares the mind for meditation (Yoga: Mind and Body).  Enter the crow by standing with your feet slightly wider than hip width and come down into a squat.  With feet flat on the floor place the hands out in front of you.  Coming up on the toes, place the hands firmly on the floor and the knees into the armpits.  Slowly shift your weight forward and bring your feet off the floor.

Similar to the crow is the peacock.  This pose enhances mental balance, concentration, and determination, removes lethargy and general feelings of weakness and helplessness and eases many mental disorders (Yoga: Mind and Body).  Sitting between the heels the arms are held out in front of you palms up with the elbows pressing against the front of the chest.  Bending forward place the hands between the knees, then slowly bring the head to the floor.  First stretch one leg behind you, then the next.  Lift the head off the floor and shift the weight of the body forward.  Keeping the legs straight, they should naturally lift off the floor.

The standing forward bend greatly enhances concentration and expels tamas (inertia or laziness), stimulating intellectual capacities (Yoga: Mind and Body).  Standing with the feet together, stretch the arms over head and bring the head to the floor.

The triangle alleviates anxiety and hypochondria as well as reduces mental stress (Yoga: Mind and Body).  With the feet shoulder width apart raise your right arm.  Slowly stretch towards the left keeping your body in alignment.  Repeat on the other side.

All yoga sessions end in what is called the corpse pose.  This is possibly one of the hardest poses as one is supposed to let go of the ego.  After an hour and a half long class, this pose is absolutely wonderful.  You lie on the floor and relax.  I find that this pose is similar to a power nap.  Lying on the floor doing nothing for a few minutes after an intense yoga session gives the body and mind a much needed break to return to baseline.

Brain cells have a high rate of metabolism, so the brain requires much more oxygen, relatively, than any other organ of the body.  The common remedy for stress is to take a deep breath; indeed, supplying the brain with sufficient oxygen is the greatest tool in stress management.  A lack of oxygen means a loss of mental balance, concentration, and control of the emotions (Yoga: Mind and Body).  Yoga: Mind and Body lists improved concentration and greater clarity of thought, increased ability to deal with complex situations without suffering from stress, better emotional control and equilibrium, and improved physical control and coordination as the mental benefits of proper breathing.  Proper yogic breathing helps to balance the two hemispheres of the brain.  One method is called anuloma viloma.  This is alternate nostril breathing and is performed by closing one nostril with the thumb and exhaling on a four count, closing both nostrils with the thumb and ring finger, and opening up the nostril the thumb is on and inhaling for a four count, exhaling on a four count, closing both nostrils and inhaling with the opposite nostril as the ring finger is released from the nose.  Ten rounds is advised.

There is a great emphasis on the spine in yoga.  Many of the exercises have you stretching the spine or twisting it around.  Spinal flexibility seems to be integral to proceeding on the yogic path.  The flow of cerebrospinal fluid (CSF) may account for the positive mental and spiritual benefits one experiences from yoga.  CSF is a clear, colorless body fluid similar in chemical composition to blood plasma and seawater.  It flows primarily within and around the central nervous system (brain and spinal cord), supplying it with nutrients and eliminating waste products.  It also physically protects the brain and spinal cord, serves as a medium for the flow of energy and information, and is the most conductive fluid in the body (Glassey, 2000).  Neuropeptides (nerve-proteins) are informational substances that are produced mostly in the brain, and are found primarily in the cerebrospinal fluid, and secondarily in the blood.  They are called “messenger” molecules, because they distribute information throughout the body, and coordinate practically all life processes on a cellular level (Glassey).  Possibly the most well known type of neuropeptide is the endorphin.  These endogenous opiates relieve pain and generate feelings of well-being.  Another aspect of CSF circulation and the aforementioned beneficial effects of yoga, involves substances called electrolytes.  Electrolytes are substances that conduct electricity when in a solution, and the CSF contains two such substances, sodium and potassium.  These electrolytes in the CSF maintain an electrical balance that controls the functioning of the nervous system, which works by the principle of electricity. The nervous system regulates and coordinates all the body's systems. Therefore, the optimum functioning of all body parts is directly related to the proper balance and circulation of the aforementioned electrolytes in the CSF (Glassey). 

Serotonin is a natural body chemical, which enhances mood and our feeling of well-being. It is released from the cells that line the walls of the ventricles, two cavities within the upper part of the brain where CSF is produced. It is also secreted from the supraependymal cells that line the central canal of the spinal cord, the major pathway of CSF. As the cerebrospinal fluid flows more freely around the brain and spinal cord, it stimulates the above-mentioned cells to release serotonin (Glassey).

In a three month study, 15 men practiced hatha yoga for 45 minutes and pranayama (breathing exercises) for 15 minutes during the morning, whereas during the evening hours these subjects performed preparatory yogic postures for 15 minutes, pranayama for 15 minutes, and meditation for 30 minutes daily (Harinath, Kain, Kumar,  Malhotra, Pal, Prasad, Rai, and Sawhney, 2004).  The control group performed flexibility exercises during the day and slow running during the day and played games for an hour at night for three months.  Serial blood samples were drawn at various time intervals to study effects of theses yogic practices and Omkar meditation on melatonin levels.  The researchers’ observations suggest that yogic practices can be used as a psychophysiologic stimuli to increase endogenous secretion of melatonin, which, in turn, might be responsible for the improved sense of well-being (Harinath et al.).  Melatonin is known not only to synchronize the organism to changing day and night cycle but has been also demonstrated to cause deep sleep-induced relaxation, lowers cholesterol levels, prevents platelet aggregation, stimulates the immune system, and is one of the most potent antioxidant hormone (Harinath et al.).

Yogic breathing provides a unique and powerful tool for adjusting imbalances in the autonomic nervous system, thereby influencing a broad range of mental and physical disorders.  By voluntarily controlling breathing patterns, it is possible to influence autonomic nervous system functions, including heart rate variability and cardiac vagal tone, chemoreflex sensitivity, baroreflex, and central nervous system (CNS) excitation as indicated by electroencephalogram (EEG), magnetoencephalography, and magnetic resonance imaging.  Neuroendocrine functions, including the release of cortisol, and possibly vasopressin and oxytocin can also be affected by yogic breathing (Brown and Gerbarg, 2005).  Our ability to control respiration consciously gives us access to autonomic function that no other system of the body can boast (Coulter, 2001).   Chemoreflex sensitivity (mediated by the vagus nerve) accounts for changes in breathing rate in response to changes in the concentration of oxygen and carbon dioxide in the blood (Brown and Gerbarg).  The baroreflex is a negative feedback system which buffers short-term changes in blood pressure.  Increased pressure stretches blood vessels which activates pressoreceptors (baroreceptors) in the vessel walls.  The net response of the CNS is a reduction of the central sympathetic outflow.  This reduces blood pressure both by decreasing peripheral vascular resistance and lowering cardiac output.  Because baroreceptors are tonically active, the baroreflex can compensate rapidly for both increases and decreases in blood pressure. 

Practicing asanas massages the internal organs, resulting in increased blood circulation, which leads to better glandular function and balanced hormone secretions.  In this way, a balance of body and mind may contribute to heart rate and blood pressure normalization.  Physical energy expended during asana practice may contribute to decreased body mass index among the control group (Hatthakit, Kasetsomboon, McCaffrey, and Rukuni, 2005).

Yoga can assist the mind in controlling the body.  Dash, Joshi, Nagendra, Naveen, Raghuraj, and Telles (2004) recruited 24 volunteers for a study on consciously lowering one’s heart rate and split into two groups of twelve.  One group was instructed to practice yoga for 30 days and the other group went about their day as usual (no experienced yogis were in either group).  At each assessment the baseline heart rate was recorded for one minute, this was followed by a six-minute period during which participants were asked to attempt to voluntarily reduce their heart rate, using any strategy.  Both the baseline heart rate and the lowest heart rate achieved voluntarily during the six-minute period were significantly lower in the yoga group on Day 30 compared to Day 1 by a group average of 10.7 beats per minute (bpm) and 6.0 bpm, respectively (p<.05, Wilcoxin paired signed ranks test).  In contrast, there was no significant change in either the baseline heart rate or the lowest heart rate achieved voluntarily in the control group on Day 30 compared to Day 1.  The results suggest that yoga training can enable practitioners to use their own strategies to reduce the heart rate, which has possible therapeutic applications (Dash et al.).

Conclusion

There is limited empirical evidence on the biopsychology of yoga and meditation, however, the scientific literature that is out there is quite convincing.  Yoga is being practiced in very much the same way today as it was 8,000 years ago.  A few differences may be a yoga studio instead of a cave and a synthetic mat instead of tiger skin.  There are many potential benefits to a yoga practice.  Aside from its spiritual aspects, one may feel relief from arthritis, or the pain in their back may be less severe.  Yoga also has a calming effect, which could keep you more placid on the roads instead of erupting into road rage.  What seems to account for these benefits is a cleaner body.  Once the insides are free of toxins, the body can operate at optimal levels. 

Disease is said to be the manifestation of imbalance in the body.  The goal of yoga is to balance not only the body but life.  As the yogi advances, deeper immersion into the poses becomes possible.  The more limber one becomes the more freely CSF can circulate and restore balance as well as enhance life experience.