Physical activity has been shown to improve asthma control in individuals with asthma. Patients with severe asthma frequently experience exacerbations, which often result in a physically inactive lifestyle. The investigators therefore hypothesize that patients with severe asthma who initiate biological therapy may particularly benefit from increased physical activity, both in terms of exercise capacity and asthma control.

The aim of this study is to determine whether an individually tailored exercise program improves exercise capacity and asthma control in patients with severe asthma. Additionally, the study evaluates the effects of the intervention on asthma symptoms, frequency of exacerbations, lung function, quality of life, and body composition.

The primary outcome is the change in exercise tolerance, measured as peak oxygen uptake during cardiopulmonary exercise testing.

Secondary outcomes include asthma symptoms (proportion of patients reporting improvement based on the Asthma Control Test), frequency of exacerbations, changes in lung function (FVC and FEV1), asthma-related quality of life (AQLQ), and changes in body composition (body mass index and waist circumference).

At baseline, all participants undergo fitness assessments, including cardiopulmonary exercise testing and muscle strength tests. Participants are then randomized into two groups. The intervention group receives an individually tailored 6-month exercise program designed by a sports medicine physician and a physiotherapist based on baseline fitness level. The control group receives standard advice to increase physical activity. Asthma medication is managed according to standard clinical practice in both groups.

Fitness assessments are repeated at 6 months for all participants, and asthma control is evaluated at 6 and 12 months

Severe asthma is a chronic condition characterized by persistent symptoms and frequent exacerbations despite optimized pharmacological treatment. In recent years, biological therapies have significantly improved asthma control in many patients. However, individuals with severe asthma often remain physically inactive due to long-standing symptoms, reduced exercise tolerance, and fear of symptom worsening. This inactivity may contribute to reduced physical fitness, poorer quality of life, and additional health problems.

Regular physical activity has been shown to improve asthma control, exercise capacity, and health-related quality of life in individuals with asthma. Despite this, structured and individualized exercise programs are not routinely included in standard asthma care. Furthermore, there is limited evidence on the effects of exercise interventions specifically in patients with severe asthma who are receiving biological therapies.

The aim of this randomized controlled trial is to evaluate whether an individually tailored exercise intervention can improve exercise capacity and asthma control in adults with severe asthma who are initiating biological treatment. The study also aims to assess the effects of the intervention on asthma symptoms, exacerbation frequency, lung function, quality of life, and body composition.

This study will be conducted at the Adult Unit of the Skin and Allergy Hospital, Helsinki University Hospital. Adult patients (aged 18 years or older) with physician-diagnosed severe asthma starting biological therapy as part of their routine care, will be invited to participate. Approximately 40-60 participants are expected to be enrolled.

After providing informed consent, participants will undergo baseline assessments, including cardiopulmonary exercise testing (spiroergometry), muscle strength testing, a six-minute walking test, and body composition measurements. In addition, participants will complete validated questionnaires assessing asthma control, asthma-related quality of life, and general wellbeing.

Participants will then be randomized in a 1:1 ratio to either an intervention group or a control group. The intervention group will receive an individualized exercise program designed and guided by a physiotherapist and a sports medicine specialist. The exercise plan will be tailored based on each participant's baseline fitness level, health status, and personal circumstances. The program will last for six months and will include follow-up support, such as a phone contact at one month and a physiotherapy visit at three months. Participants will also be provided with tools such as an exercise diary and a step counter to support adherence.

The control group will receive standard care, including general advice on the benefits of physical activity, but no structured or personalized exercise program. All participants in both groups will continue their usual asthma treatment, including biological therapy, according to standard clinical practice.

At six months, all baseline assessments will be repeated to evaluate changes in physical fitness and other outcomes. Asthma control will be further assessed at 12 months.

The primary outcome of the study is the change in exercise capacity, measured as peak oxygen uptake (VO₂peak) during cardiopulmonary exercise testing. Secondary outcomes include changes in asthma symptom control, frequency of exacerbations, lung function (FVC and FEV₁), asthma-related quality of life, and body composition (body mass index and waist circumference).

All data will be collected and managed securely in accordance with data protection regulations. Participation in the study is voluntary, and participants may withdraw at any time without affecting their standard medical care.

The results of this study will provide new evidence on whether personalized exercise interventions can enhance the benefits of biological therapy in severe asthma and support the development of more comprehensive, patient-centered treatment strategies.

Inclusion Criteria:

• Age over 18 years
• Physician-diagnosed severe asthma defined with the GINA criteria and with a decision to initiate biological treatment (omalizumab, mepolizumab, benralizumab, dupilumab or tezepelumab) for severe asthma

Exclusion Criteria:

• Upcoming major surgery
• Acute musculoskeletal disease which unables regular exercise
• Inability to commit to the appointments and the exercise plan due to exhaustion or fatigue
• Pregnancy

the data collected will only be used in the study publications.