Efficacy of L-menthol on Breathlessness in Asthma

The purpose of this study is to assess the effect of L-menthol on breathlessness and exercise capacity in patients with Asthma.

Inclusion Criteria: * the subject has given written consent to participate in the study * physician diagnosis of Asthma according to international guidelines * mMRC (modified Medical Research Council) score of 1 or above * age 18 years or older * able to cycle * able to understand and talk Swedish to participate in the study procedures, as judged by the Investigators. Exclusion Criteria: * resting peripheral oxygen saturation (SpO2) \< 92% * hospitalization or clinical instability during the last four weeks * treatment with supplementary oxygen at rest or during exercise * contraindication to exercise testing in accordance with clinical practice guidelines * expected survival shorter than six months as judged by the Investigator * medical conditions including congestive heart failure, acute coronary artery disease, neuromuscular diseases, severe psychiatric illness, and olfaction disorder.