Yoga regards the body as a vehicle for the soul and asana (yoga postures) are designed to develop not only the body, but benefit the health of the mind and spirit.
The movements in yoga are non-violent; other forms of exercise produce a build up of lactic acid in the muscles causing tiredness as well as physical wear and tear on the body.
Yoga postures focus on the health of the spine, keeping it strong yet flexible and correctly aligned. The spinal column houses the spinal cord, which is like the Centre of communication for the body as it sends out nerve currents. This is why asana helps to promote a relaxed nervous system, keeps stress at bay by supplying the spinal cord with a rich source of oxygen and nutrition through the various postures.
Asana also works on the internal mechanics of the body, the glands, the organs, as well as the muscles. It has a far greater effect on the more subtle parts of the body which other exercise does not do. The internal organs receive massage and simulation through various movements, especially in twisting postures and forward bends. The endocrine system (glands and hormones) is rejuvenated, especially in postures that invert the body, where the heart is higher than the head. This in turn balances our emotions, improving our mental outlook.
The breathing exercises practiced in yoga called Pranayama also nourish the nervous system. An increased amount of oxygen and Prana (life force) is stored in the body increasing cellular rejuvenation and slowing down the aging process.
Our mind is greatly affected by our breath and yogis for thousands of years have practiced control the mind by control of the breath. Every part of the body can be filled with Prana and when we are able to do this, the whole body will be under control. It is said that all diseases of the body can be destroyed at the root by controlling and regulating the Prana; this is the secret knowledge of healing.
But not only is exercise and breathing important to our health we need also to learn the art of deep relaxation. This happens on three levels; physical, mental and spiritual. To relax physically in the posture of Savasana has unending benefits, our muscles relax, and even our internal organs go into deep relaxation.
On a mental level we let go of our stress and mental tiredness, the mind becomes calm and clear. On a spiritual level, we start to let go of our self-identification with the body and mind, letting go of our individual ego.