A 5000 years old seal found from the Indus valley sites shows Lord Shiva performing a very difficult Yogasana pose called as Mulbandhasana in which the feet are folded backwards (inset).
This is a highly advanced form of Yoga and Meditation which must have taken a very long time to evolve, and thus Yoga can be approximated to be at least 6000 years old. So back in this time, our people had deep insights about the functioning of human body in the form of Yoga. They also knew how practicing Yoga can lead to a healthy life. The amazing thing is that the effectiveness of this 6000 years old Indian Science is proven accurate even today!!