Background: Chronic inflammatory airway diseases (CIAD) are well-known risk factors for depression symptoms. There exists a complex interplay between leisure-time physical activity (LTPA) and depressive symptoms. However, the relationship between LTPA duration and depressive symptoms in CIAD patients remains unclear. Objectives: This study investigated NHANES data from 2007 to 2018 to investigate the relationship between LTPA and depressive symptoms in CIAD patients. Methods: We collected data from National Health and Nutrition Examination Survey (NHANES) 2007-2018. Weighted logistic regression was employed to analyze the correlation between CIAD and depressive symptoms. Next, CIAD patients with LTPA information, the similar method was also employed to examine the association between LTPA and depressive symptoms. Finally, the dose-response relationship between LTPA duration and depressive symptoms was explored using restricted cubic spline (RCS) plot. Results: Consistent with previous research findings, patients with CIAD are more prone to experiencing symptoms of depression (P < 0.0001). Compared to CIAD patients without LTPA, patients who engage in LTPA have a lower probability of experiencing depressive symptoms (P < 0.0001). Interestingly, we had discovered that there is an l-shaped relationship between the duration of LTPA and the prevalence of depressive symptoms (non-linear P = 0.001). There is a threshold effect between the duration of LTPA and depressive symptoms. Within12 h/week, the risk of depressive symptoms in CIAD patients decreases with increased duration of LTPA. However, beyond 12 h/week, this association no longer exists. Conclusion: Our research indicates that CIAD patients can increase the prevalence of depressive symptoms. And LTPA over a period of time is negatively correlated with depressive symptoms, but only up to a total duration of 12 h/week.