Introduction: Regular aerobic physical activity (PA) improves asthma control and lung function, and is recommended as a supplementary treatment in asthma. Thus, we wanted to investigate if these beneficial effects could facilitate a reduction in the use of inhaled corticosteroid (ICS).

 
Objective: To evaluate the corticosteroid-sparing effect of vigorous physical activity in patients with asthma.

Methods: Participants from a previous RCT exercise study reported physical activity level at baseline and after 6 months of either 3/week HIIT exercise or control (2:1). All participants had their ICS dose adjusted based on asthma symptom score every second month. A secondary exploratory multiple linear regressions analysis adjusted for baseline ICS treatment and stratification factors was applied to evaluate the corticosteroid-sparring effect of change in vigorous physical activity.

Results: Of 150 randomised patients, 121 were included (82 exercise group, 39 control). Mean age 49 (SD 16), 61% female sex. An increase of 1 min/week in vigorous PA associated to a change of -1·7ug (95% CI -3·4 to -0·0; p=·047) in ICS dose. Adjusting for baseline vigorous PA improved the association (-1·9 ug/min/week [95% CI -3·7 to -0·1]; p=·044). Further adjusting for moderate PA weakened the associated (-1·7ug/min/week [95% CI -3·5 to 0·1]; p=·068). With an increase of 60 minutes per week associated to a decrease in ICS-dose by approximately 110 µg. Baseline ACQ-score (p=·0002) and ICS dose (0·003) were significantly associated to change in ICS-dose.

Conclusion: Increase in vigorous physical activity associated to a reduction in the use of ICS