What is ashtanga yoga and benifits of it ?

Yoga is a health-enhancing practice to those who are 50 years and older.
In Sanskrit, ashtanga means eight-limbed (asta– eight, anga– limb). Ashtanga Yoga is an eight-limbed path towards achieving the state of Yoga, also known as Samadhi.
The definition of Ashtanga Yoga is found in the Yoga Sutras of Patanjali, an ancient text on the theory and practice of Yoga thought to have been compiled in about 200 CE by Sage Patanjali.
The Yoga Sutras begin with the highest teachings first, for those ready to enter into the final limbs of practice. In the second sutra of the first chapter, Samadhi Pada, we are offered the definition of Yoga: “Yogas citta vritti nirodah”, which means Yoga is the cessation of the fluctuations of the mind.
Yoga is found in book two of the Yoga Sutras of Patanjali -Sadhana Pada.The eight limbs of yoga are Yama, niyama, asana, pranayama, pratyahara, dharana, dyana and samadhi.
1)    Yama– Restrains or observances regarding how the aspiring yogi should relate to his or her community.
 The yamas are:
Ahimsa– Non-violence
Satya– Truthfulness
Asteya– Non-stealing
Brahmacharya– Conservation of vital energy
Aparigraha– Non-hoarding
 
2)    Niyama– Intense observances that the aspiring yogi should carry out in his or her daily life in order to have a body and mind suited for Yoga.
The niyamas are:
Saucha– Cleanliness of body and mind
Santosha– Contentment
Tapas– Discipline
Svadhyaya– Self-study
Ishvara Pranidhana– Surrender to the Divine
3)    Asana– The word literally translates to “seat”. These are meditative postures that promote stillness of mind, and physical postures that facilitate sitting for long periods of time in those meditative postures.
4)    Pranayama– Prana is life force/breath/vital energy, and Yama is restraint. Pranayama translates to extension of the life force. Pranayama are breathing practices that involve the retention of breath.
5)    Pratyahara– Withdrawal of the senses from things that are not conducive to the practice of Yoga, a moving from the external to internal world. When the 5 senses are quelled, the mind can then become still.
6)    Dharana– Concentration on a single thing, ideally something spiritual in nature.
 
7)    Dhyana– Meditation.  Uninterrupted, flowing concentration in which the meditator begins to merge with the object of meditation.
8)    Samadhi– A super-conscious trance in which the mind merges fully with and becomes one with the object of meditation. In the highest state of Samadhi, there is no longer any object of meditation.
 
Benefits of Astanga Yoga
The eight limbs are a process of going deeper and deeper inward to discover and abide in the Divinity within us. When we come to rest in Yoga, we are in a state of perfect oneness, beyond peace, beyond bliss.
Ashtanga yoga has numerous health benefits for practitioners like
Improves flexibility over time, as with most forms of yoga
Increases body strength, Improves cardiovascular fitness, Reduces body fat, Reduces stress and anxiety, Increases focus and creativity, Increases muscle tone, Lowers blood pressure.
Finally, beware of youtube made Yoga teachers, follow only experienced Yoga gurus who follow only classical, ancient texts of our ancient sages, who respect our culture and traditional texts, from which Yoga evolved.