Yoga is one of the four branches of Hinduism.
It is for people who have decided to fast-track their spiritual growth .. the goal is to dissolve our ego and merge with the Divine.
The goal of Yoga is NOT to improve health, relax, or become happier. But that is what Westerners use it for, and there is no harm in that. It is, perhaps, best though if they understand that what they call "Yoga" is not, in fact, actual Yoga. A lot of us get very smug about doing Yoga, and don't realize that we aren't really DOING it.
Of course, what MOST people CALL "yoga" are the stretching exercises.
This is actually HATHA yoga . .it was designed to stretch out muscles after the yogi had been sitting in meditation for 8-10 hours.
There are several sub-sets of the practice of Yoga:
- Hatha - the exercises to stretch out stiff, unused muscles
- Karma - Karma Yoga is the attitude of doing whatever God has placed before you TO do, without attachment to reward or results. To do it because it is the right thing to do, and to do it unselfishly.
- Jnana - Jnana Yoga is scriptural reading and study, but also mental discrimination as you go through your day, reminding yourself of what matters and what is not important
- Bhakti - Bhakti Yoga is cultivating devotion to God ... mostly through chants
- Raja - Raja Yoga is meditation and is THE primary method for spiritual growth and transformation. Those who truly practice Yoga DO Raja Yoga ... and most of the other forms, as well. But it is the meditation that is the foundation for all the other forms of Yoga.
There are other kinds of yoga, named after distinct meditation techniques. For instance, Paramhansa Yogananda brought "Kriya yoga" meditation to the west 100 years ago (my mother was one of his students), and Kriya is a specific type of meditation. You must be taught and initiated by someone who is qualified in order to do this meditation.
But there are other types of specific meditation techniques with their own names .....
My mother practiced yoga all her life, in a semi-serious way. She didn't start doing Hatha yoga until she was in her 50's and starting to lose physical flexibility. But she did Raja yoga from age 20 (when she met Yogananda) until her death.
I practiced for about 7 years, but found that Buddhism works better for ME.