Science of Pranayam, Meditation

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Each cell in our body also requires energy (called Prana) to survive. This energy is created in a specific part of the cell called Mitochondrion which uses oxygen to oxidize glucose.

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 If the quality or quantity of oxygen reaching the cell is less, the energy output is also less. But since energy cannot be compromised, the mitochondria immediately demands more oxygen and hence the lungs inhales (refills) air again and the cycle repeats.body & energy efficiency can be improved by:
1) Improving blood circulation
2) Improving capacity of lungs
Although Asanas address the blood circulation throughout the body, there are several internal organs & tissues which are beyond the scope of Asanas. For example, we need different techniques (other than asanas) to rejuvenate the the brain cells, nervous system & nadis. This is where Pranayama comes to the rescue. Pranayamas are basically breathing exercises which involves combinations of inhalations, exhalations, vigorous breathing, breath control and more. Just like how we have several asanas, we also have several pranayamas, each catering to certain aspect. Each pranayama can either improve blood circulation or improve lung capacity or do both.

For example, Kapalabhati pranayam improves blood circulation in the brain while Bhastrika pranayam improves lung capacity. Ujjayi regulates blood pressure whereas Anulom Vilom cleanses & tones the nervous system. This way, practicing the right set of pranayamas can eventually result in increased lung capacity & improved blood circulation.

It is widely acknowledged that Yogis, despite having similar lung size as that of an average human, can inhale 3-4 times more air because regular practice of Pranayama would have increased their lung capacity i.e They fill their lungs completely (almost 100%) with air during every inhalation, and exhale it completely before the next inhalation.
Renowned Yoga master BKS Iyengar demonstrates his lung capacity in this 2 min clip:
https://www.youtube.com/watch?v=fcPjvp4La8A

With increased lung capacity & improved blood circulation, the breathing rate (number of times the lungs are refilled) decreases. As with any machine which has wear & tear and a shelf life, our body also has a shelf-life which is proportional to the number of breaths it takes throughout its lifetime.

study of Pranayama has gained prominence in the medical field, with experiments ranging from measuring reaction time, to long term analysis of health benefits. Due to the acknowledgement of the benefits of Pranayama by medical sciences, it is being recommended by doctors throughout the world and Yoga teachers with entrepreneurial minds have turned it into big business.



http://www.ijpp.com/IJPP%20archives/2003_47_2/229-230.pdf
Despite several such proofs & acknowledgement of the benefits of Pranayama in the western world, surprisingly, it is yet to be recognized in its own country i.e India.
When it was recently introduced in Indian schools (along with Yoga), there was a severe backlash from several communities in the name of secularism and the matter is now in the Supreme Court to decide whether Yoga & Pranayama can taught in schools or not.



http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3939514/pdf/jcdr-8-10.pdf



Source-Modified from guruprasad.net