Yoga is not just stretching and exercises, yogasana in just one among eight 'angas' of yoga.
Yoga is the way to achieve the highest state “Samadhi” (Sama– Even,Dhi–intellect) – Moksha (liberation, release or freedom fromSamsara) - The state of super consciousness – enlightenment – absolute calmness.
The meaning of the word "Yoga" is "union". It is derived from the Sanskrit root "yuj," meaning "to join", "to unite", "to control".
In the Bhagavad Gita, yoga is also defined as "skill in action" and "moderation in everything" (avoidance of excesses).
The most famous definition of Yoga is in the Yoga Sutra, the ancient text attributed to the sage Patanjali: Yogas Citta Vrtti Nirodhah, "Yoga is the restraint of the agitation of thoughts".
Yoga is an art and science dedicated to creating harmony between body, mind and spirit.
In short it is about creating absolute calmness so as to live in peace & good health.
Bhagavat gita distinguishes several paths to attain yoga corresponding to the duties and different nature of people.
Jnana Yoga is the path for self-realization trough ultimate wisdom & knowledge.
Way of Moksha with extreme selfless devotion.
3. Karma Yoga
Karma yoga is the most effective way to progress indulging in duties. By which Samadhi can be achieved by doing karma with selfless motive.
KarmaYoga is a path of self-realization by involving in “Karma” (a word, to express a work including its results) without Kāma (Lust), Krodha (Anger), Mada (Egocentric), Moha (Delusion), Mātsarya (Envy) and Bhaya (Fear).
4. Raja Yoga
Raja Yoga is the way to reach enlightenment by ultimate concentration –
In raja yoga we use our mental powers to realize the Atman through the process of psychological control.
In the 19th-century Swami Vivekananda equated raja yoga with the Yoga Sutras of Patanjali. Since then, Raja yoga has been called "aṣṭanga yoga"
Maharshi Pathanjali explaines the eight steps (Ashata Anga) for achieving yoga sidhi.
"Yama, Niyama, Asana, Pranayama, Pratyahara, Dharana, Dhyana and Samadhi".
1. Yama yoga
The first limb, yama, deals with one’s ethical standards and sense of integrity, focusing on our behavior and how we conduct ourselves in life.
The five yamas are:
Asteya: undesire of others belongings.
Brahmacharya: Following Brahma
Aparigraha: Non possessives
2. Niyama yoga
Niyama, the second limb, has to do with self-discipline and spiritual observances. The five niyamas are
Samtosa: happiness and satisfaction.
Svadhyaya: Own reading" and self-study
Isvara pranidhana: Devotion to God
3. Asana Yoga
Asana refers both to the place and the posture in in which a yogi sits, Asanas are performed as physical exercise called as "yoga postures" to promote good health.
4. Pranayama Yoga
“Breathing is the physical part of thinking and thinking is the psychological part of breathing”
Pranayama is the way of controlling breath.
How Taming the Mind is Like Riding a Horse, controlling mind with breath and horse with bridle.
These first four stages of Patanjali’s ashtanga yoga concentrate on refining our personalities, gaining mastery over the body, and developing an awareness of ourselves, all of which prepares us for the second half of this journey, which deals with the senses, the mind, and attaining a higher state of consciousness.
5. Pratyahara yoga
Withdrawal of senses(Indriya), Prathyahara is withdrawing the senses from external subjects. Pratyahara practices lead to higher state of relaxation, expanded selfawareness, and inner stability which leads to dharana.
6. Dharana yoga
Concentration of mind, Dharana is the process of holding or fixing the attention of mind onto one object or place.
That is single-pointed concentration; extended periods of concentration naturally lead to Dhyana.
7. Dhyana yoga
Meditation, Dhyana is continuous single pointed concentration.
8. Samadhi yoga
Samadhi is attained by dhyana.
Samadhi cones from saskrit words sama and dhi – sama meaning absolute calmness and dhi meaning buddhi or the intellect.
Samadhi is the absolute calmness state of intellect.
Modern days researches on yoga
Effect on default mode network
Default mode network or default state network, is a large scale brain network of interacting brain regions known to have activity highly correlated with each other and distinct from other networks in the brain. Functions include episodic memory, imagining of future, social evaluations etc. Latest studies show that the default mode networks which stimulate the wandering and aimless thoughts was made quite resulting in peaceful thoughts.
Effect on Amygdala
Amygdala is one of the two almond shaped groups of nuclei located deep and medially within the temporal lobes of the brain. They are responsible for perception of emotions such as anger, fear, sadness etc. Latest study has revealed that meditation results in decrease in size of amygdala and indeed its activity.
Effect on Grey matter
Grey matter is a major component of the central nervous system consisting of neuronal cell bodies,neuropils,glial cells,synapses and capillaries It involves muscle control,sensory perception,decision making,self control etc. Recent advancement has claimed yoga to increase the quantity of grey matter thus increasing the sensory perception.
When we are considering the benefits of yoga Samadhi is the ultimate. But some benefits which we can surely expect, improved flexibility, strength, immunity, sleep, balance, peace, focus, happiness & reduced stress, blood pressure, blood sugar, disease etc.