The three stages of sadhana correspond with the eight limbs of Ashtanga yoga. The first three limbs - yama, niyama and asana - correspond with bahiranga sadhana. The next two limbs - pranayama and pratyahara - correspond with antaranga sadhana. The last three limbs - dharana, dhyana and samadhi - correspond with antaratma sadhana.
Bahiranga sadhana involves practices that use the body and prana to advance in a spiritual practice. Antaranga sadhana consists of practices that aid in deep study and cultivating the mind. Antaratma sadhana, the quest of the soul, promotes concentration, improves self-awareness, curbs external thoughts and achieves Self-realization. Antaratma sadhana helps the yogi to feel one with universe and experience eternal bliss.