Yoga is not a religion

Karma Yoga, Bhakti Yoga, Jnana Yoga and Raja Yoga are considered the four main Yogas, but there are many other types. Yoga is not a religion though it is central to Hinduism. In Hinduism, Yoga is considered to be a path to attain enlightenment. The earliest written accounts of Yoga appear in the Rig Veda, which began to be codified between 1500 and 1200 BC. Important Hindu texts establishing the basis for Yoga include the Upanishads, Yoga Sutras of Patanjali, the Bhagavadgita and the Hatha Yoga Pradipika.

The word "Yoga" derives from the Sanskrit root yuj ("to yoke"). It is translated as "union of the individual Atma or soul with the Paramatma, the universal soul. In essence, one who performs Yoga may loosely be referred to as a Yogi or in Sanskrit as Yogin for male and Yogini for female. These designations are actually intended for advanced practitioners who have reached a certain spiritual level. Some notable Yogis were Shankaracharya from the Jnana Yoga tradition; Ramakrishna Paramahamsa was a Bhakti Yogi and Sri Aurobindo developed and practiced Integral Yoga, a culmination of the four main Yogas. The Bhagavadgita famously distinguishes several types of "Yoga", corresponding to the duties and nature of people, capturing the essence and at the same time going into the details about the various Yogas and the philosophies behind them. starofmysore.com