The purpose is to characterize the change of respiratory admittance induced by salbutamol inhalation in children and young adults. A variation threshold will be fixed to distinguish asthmatic and healthy subjects.

This project could allow a better identification of asthmatic individuals needing a treatment, a reduction of morbidity of asthma, a reduction of unnecessary treatments administered in individuals with respiratory but not asthmatic symptoms, a better comprehension of bronchial hyperreactivity and its role in asthmatic disease.

Inclusion Criteria:

Asthmatic children group:

• Several episodes of paroxysmal wheezes, spontaneous or after exercise, without bronchial-pulmonary infection
• Absence of bronchodilator taking during last 12 hours
• Absence of reported intolerance to adrenergic substances
• Parental authorization and consent of child to participate to the study

Control children group:

- Parental authorization and consent of child to participate to the study

Control adult group:

- Consent to participate to the study

Exclusion Criteria:

Control children and adult groups:

• At least 2 episodes of wheezes during breathing
• Several wheezes, abnormal breathlessness, cough during physical exercise
• Asthma diagnosed by family doctor
• Administration of drugs to treat asthma
• Eczema or food allergy at inclusion
• Episode of cough for longer than 6 weeks, without bronchial infection
• Bronchitis, throat infection, rhino-pharyngitis during last 15 days
• Paleness or cyanosis with loss of consciousness when the child was a baby or during an exercise