For EIA patients  Inclusion Criteria:  written agreement age >=12 and <= 24 known exercise induced asthma Group 1: skin prick test positiv house-dust allergy, eNO > 30 ppb, MCT PD20 < 0,1 mg Group 2: skin prick test negative house-dust allergy, eNO < 20 ppb, MCT PD20 < 1 mg lung function before ECC forced vital capacity (FVC) ≥ 75% and forced exspiratory pressure in one second (FEV1) ≥ 70%  Exclusion Criteria:  age < 12 und > 24 years lung function FVC < 75% und FEV1< 70% inability to understand the range of the study chronic asthma with systemic cortisone therapy regular therapy with inhalative corticosteroids or leukotriene-antagonists <14 days before visit 1 intake of long acting beta-agonists (LABA) 48 h before examination intake of short acting beta-agonists (SABA) 8 h before examination acute severe infection (pneumonia) within the last 4 weeks other chronic diseases or infections (HIV, Tbc) pregnancy  For healthy controls  Inclusion Criteria:  written agreement age >=18 and <= 24  Exclusion Criteria:  age < 18 and > 24 years known asthma bronchiale or other chronic lung diseases lung function FVC < 90% and FEV1 < 80% allergic sensitization in skin prick test eNO > 30 ppb inability to understand the range of the study acute severe infection (pneumonia) within the last 4 weeks other chronic diseases or infections (HIV, Tbc) pregnancy