Many people might mention things about awareness and generating positive energy when discussing the yoga practices (which I think are the most prominent aspect to practicing asanas), but I also think the spiritual component is also worth mentioning. Yoga essentially means “union”, specifically with God or the Ultimate Reality. The goal is to reach self-actualization, transcendence, nirvana, liberation…
And if we are speaking about yoga as a whole, and not just about one of its limbs “asana” (one out of eight limbs), then there are three other limbs to consider that focus specifically on mental ability or the process of meditation. Dharana (concentration), Dhyana (meditation), and Samadhi (transcendent state of consciousness).
Because I have studied yoga within my degree program, I do not believe it can be considered an exercise by any means if you know the spiritual discipline it entails. Exercise requires concentration, but not the same type of concentration that leads to a meditative trance that yoga does.
I don’t normally associate yoga as a form of exercise… its more of a physical activity if you are in a high paced class such as vinyasa or ashtanga. But even when the pace or style of the class goes unmentioned, a large majority would categorize yoga as more of a relaxation tool or a form of therapy first!
It’s up for debate, so let me know what you think!