Summary
Background: There is a lack of knowledge on the association between daily physical activity and lung function in patients with asthma.
Objective: This study aims to examine the association between daily physical activity and asthma control, lung function, and lung function decline in patients with adult-onset asthma.
Design: This study is part of Seinäjoki Adult Asthma Study (SAAS), where 201 patients were followed for 12 years after asthma diagnosis. Daily physical activity was assessed at follow-up by a structured questionnaire and used to classify the population into subgroups of low (≤240 min) or high (>240 min) physical activity. Three spirometry evaluation points were used: 1. diagnosis, 2. the maximum lung function during the first 2.5 years after diagnosis (Max0-2.5), 3. follow-up at 12 years.
Results: High physical activity group had slower annual FEV1 (p<0.001) and FVC (p<0.018) decline. Additionally, the high physical activity group had higher FEV1 values at follow-up, and higher FEV1/FVC ratios at follow-up and diagnosis. There was no difference in BMI, smoking, medication, or frequency of physical exercise between high and low physical activity groups. Differences remained significant after adjustments for possible cofounding
factors.
Conclusion: This is the first demonstration of an association between long-term FEV1 decline and daily physical activity in clinical asthma. Low physical activity is independently associated with faster decline in lung function. Daily physical activity should be recommended in treatment guidelines in asthma.

Relevance
The study compared the (self-reported) physical activity of asthmatics to their spirometry findings 2.5 and 12 years after the diagnosis, that is, not only the subjective asthma control score. This was, to our understanding, a new approach. The authors refer to earlier studies on asthma and exercise from year 2013 and onwards, the time when it first was realised that exercise is not harmful in asthma, as previously thought. The mechanisms in which exercise benefits the asthmatics and may even reduce the inflammation has since been elaborated on in other studies. This paper contributes to the valuable knowledge that the asthma treatment guidelines, patient education and self-care recommendations are based on now and in the future.