Dyspnea in asthma, is mainly due to airway obstruction but can be caused by several alternative diagnoses.

The impact of sarcopenia on dyspnea in patients with asthma is unknown. Sarcopenic asthma had a reduced physical activity and is associated with airway obstruction compared to non-sarcopenic asthma. In patients with obstructive pulmonary disease, sarcopenia is associated with shallow breathing and diverse sensory and affective components of exertional dyspnea .

The morbidity of sarcopenia is also increased by systemic inflammation and the production of inflammatory cytokines as found in inflammatory airway obstruction.

The investigators will investigate the prevalence and impact of sarcopenia in asthmatics patients. This will enable to better manage sarcopenia in asthmatic patients, understand its origins and personalize treatment.

Inclusion Criteria:

• Age ≥ 18 years
• Patient affiliated to a social security scheme.
• Patient capable of giving free, informed, written and signed consent.
• Asthmatic patients with a diagnosis made by a pulmonologist on GINA level 4 or 5 treatment
• ACT asthma control score < 20
• Patient judged by the investigator to be able to to perform a maximal exercise test.

Exclusion Criteria:

• Patient under guardianship/trusteeship/supervision of justice
• Pregnant or breast-feeding women
• Unstable heart disease
• Patients who have been smoking or have stopped smoking for less than 5 years,