Developed in India, yoga is a spiritual practice that has been evolving for the last 5,000 years or so. The original yogis were reacting, in part, to India's ancient Vedic religion, which emphasized rituals. The yogis wanted a direct spiritual experience -- one on one -- not symbolic ritual. So they developed yoga.
Yoga means "union" in Sanskrit, the classical language of India. According to the yogis, true happiness, liberation and enlightenment comes from union with the divine consciousness known as Brahman, or with Atman, the transcendent Self. The various yoga practices are a methodology for reaching that goal.
In hatha yoga, for example, postures and breathing exercises help purify the mind, body and spirit so the yogi can attain union. Pranayama breathing exercises help clear the nadis, or channels, that carry prana the universal life force, allowing prana to flow freely. When the channels are clear and the last block at the base of the spine has been opened, Kundalini rises through the spine, through the central channel called the sushumna-nadi, and joins the crown chakra. According to the tradition, the release of Kundalini leads to enlightenment and union.
For starters, yoga is good for what ails you. Specifically, research shows that yoga helps manage or control anxiety, arthritis, asthma, back pain, blood pressure, carpal tunnel syndrome, chronic fatigue, depression, diabetes, epilepsy, headaches, heart disease, multiple sclerosis, stress and other conditions and diseases. What's more, yoga:
Improves muscle tone, flexibility, strength and stamina
Reduces stress and tension
Boosts self esteem
Improves concentration and creativity
Lowers fat
Improves circulation
Stimulates the immune system
Creates sense of well being and calm.