Lung function test (LFT) is a good picture of how much air moves in and out of lung and how efficiently oxygen is moved in and carbon dioxide is moved out. The published guidelines for measuring PEF by American thoracic society provide no precise recommendations about the speed of inspiration preceding expiration and the appropriate duration of the post inspiratory pause. Although long post inspiratory pauses (> 3s) are generally not used, pauses of < 2s are often allowed prior to expiration in most pulmonary laboratories. Studies in healthy volunteers showed that inspiratory maneuver preceding forceful expiration could affect the magnitude of lung volumes. Many studies in healthy individual as well as in patients of different disease like asthma, COPD and cystic fibrosis shows that fast inspiration followed by fast expiration without pause gives a more values rather than long post inspiratory pause (>3s). Whereas according to American thoracic society, pause of <2secs is generally used, >3s inspiratory pauses are not recommended. So the study was to find out which maneuver, fast maneuver without pause or slow maneuver with pause of <2sec is more effective in lung function test.