Exercise tests are indicated to determine the etiology of dyspnea, document the presence or absence of exercise induced asthma, assess response to therapies and training, document progression of diseases and assess risk of lung resectionThree groups have been tested for this study: COPD group, Bronchial asthma group and Control group.The analysis of the ventilatory functions studies revealed that: There are statistical significant differences in VC %, FVC%, FEV1% FEV1/FVC% and PEF % between COPD group and control group. There are statistical significant differences in VC %, FVC%, FEV1%, MEF75%, PEF% and MIF 50 between COPD group before and after pulmonary rehabilitation program.There are statistical significant differences in FEV1%, FEV1/FVC%, PEF% between Bronchial asthma group and control group. There are statistical significant differences in FVC%, FEV1% and PEF% between Bronchial asthma group before and after pulmonary rehabilitation program.