Pratyahara is the fifth limb of Ashtanga Yoga. Pratyahara means drawing back or retreat. The word ahara means "nourishment"; pratyahara translates as "to withdraw oneself from that which nourishes the senses." In yoga, the term pratyahara implies withdrawal of the senses from attachment to external objects. What does this mean? It means our senses stop living off the things that stimulate; the senses no longer depend on these stimulants and are not fed by them any more.

Let us look at this concept a little closely. When we see a sunset, first our eyes are drawn to it; the eyes sent a message to the brain; the brain computer will assimilate the information sent by the eyes and form the picture of the sunset. This is the way our senses function normally. But there is also the possibility that the most beautiful sunset on earth will not attract our attention, will not engage our senses, because we are deeply immersed in something else. We may be concentrating on something without any awareness of what is going around us. Normally the senses say to the mind: "Look at this! Smell this! Touch that!" The senses register an object and the mind is drawn to it at once.

In pratyahara we sever this link between mind and senses, and the senses withdraw. Each sense perception has a particular quality to which it relates: the eyes relate to the form of something; the ears to the sound, the vibration it makes; the nose to its smell. In pratyahara it is as if things are spread out with all their attractions before our senses, but they are ignored; the senses remain unmoved and uninfluenced. In effect the brain will disregard all that is received by the various sensory organs and will only accept and process the signals sent by sensory organs at the command of the brain. Now we have control over our senses rather than being controlled by them.

For example, when we are totally absorbed in the breath during pranayama, pratyahara occurs quite automatically. The mind is so intensely occupied with the breath that all links between mind, senses, and external objects that have nothing to do with the breath are cut off. So pratyahara is not a state of sleep. The senses are quite capable of responding, but they do not because they have withdrawn or detached.