Pran-Universal life energy  

Ayam- To Extend and elongate(lengthen)

In short pranayama means an exercise which is to be performed if you want to extend your life.

When Seven chakras are rotating as windmill to produce energy to our body, this prana work as wind.While breathing we take the oxygen along with all important pervading prana and exhale the toxins from the body. Pranayama helps to calm down the mind , improve memory,virility, and strengthens our neurological system.