Respiration includes inhalation and exhalation. In between these two processes there is a very minute gap or pause (normally in milliseconds) which is usually not noticed and it recurs, i.e., inhalation-pause-exhalation-pause-inhalation.... and it continues. The maximum gap or pause is observed in the state of rest. Kumbhak enforces to increase the pause by ceasing the breath routinely and continuously by various types of pranayama and kumbhaka exercises.
It has been said that It is being observed that more the time spent for pranayama (and kumbhaka); more is the concentration and better is the control over mind.. Various ancient yogis (expert in yoga and pranayama) noticed the importance of respiration and its correlation with activities of mind and vital forces. Aging is also seen proportional to frequency of respiration or respiratory rate, i.e., frequency of inhalation and exhalation in one minute. Medical science recorded normal respiratory rate in humans as 12-16 breaths per minute with life span of 70–80 years. These figures may vary due to geographical, communal and other distribution factors.