Exercise Improves Small Airway Function in COPD

EXERCISE training may improve peripheral airway function in patients with chronic obstructive pulmonary disease (COPD), according to new research involving 62 participants.

The prospective multicentre study found that a 12-week supervised exercise programme significantly improved several measures of small airway function, alongside exercise capacity and patient-reported symptoms. Notably, these improvements were detected using impulse oscillometry (IOS), while conventional spirometry and lung volume measurements remained largely unchanged.

Investigating Exercise Benefits Beyond Muscle Conditioning

Exercise is an established component of COPD management, with recognised benefits for exercise tolerance, symptoms, and quality of life. However, the physiological mechanisms underlying these improvements remain incompletely understood.

In particular, small airway dysfunction and structural changes in the peripheral lungs may not be adequately captured by conventional spirometry. IOS, which measures respiratory resistance and reactance during normal breathing, may offer greater sensitivity to changes in airway mechanics.

Researchers therefore investigated whether a structured exercise intervention could produce measurable improvements in peripheral airway function.

The prospective, single-arm, non-randomised study included 62 patients with COPD who completed a 12-week programme consisting of three supervised sessions per week. Training was individually tailored and combined moderate-intensity aerobic exercise with muscle-strengthening activities.

Participants underwent assessments of lung function, exercise capacity, and respiratory symptoms before and after the intervention.

Small Airway Function Improves After Exercise

Following the intervention, significant improvements were observed across several IOS parameters associated with airway resistance and peripheral lung mechanics.

Total respiratory resistance at 5 Hz (R5) decreased by a median of 0.75 z-score (p=0.001), while the difference between resistance at 5 Hz and 20 Hz (R5–R20), a measure associated with peripheral airway dysfunction, decreased by 0.18 z-score (p=0.007).

Resonant frequency (Fres) also improved, decreasing by 0.33 Hz (p=0.022), alongside a reduction in the area of reactance (AX) of 0.05 kPa·s⁻¹ (p=0.042).

In contrast, conventional lung function measures showed limited changes. Spirometry and lung volumes remained largely stable, apart from a small but statistically significant improvement in forced vital capacity (FVC; +0.12 z-score; p=0.027).

These findings suggest that IOS may detect physiological adaptations following exercise training that are not readily apparent through conventional pulmonary function testing.

Exercise Capacity and Symptoms Also Improve

Beyond improvements in airway mechanics, participants demonstrated significant gains in functional exercise capacity.

Six-minute walk distance increased by 15 m (p=0.002), while performance on the 1-minute sit-to-stand test improved by three repetitions (p<0.0001).

Patient-reported respiratory symptoms also improved. The COPD Assessment Test (CAT) score decreased by 1.0 point (p=0.014), while the Clinical COPD Questionnaire (CCQ) score decreased by 0.1 points (p=0.011).

Although these changes were statistically significant, the average improvements in walking distance and symptom scores were relatively modest.

The researchers concluded that supervised exercise training was associated with improvements in peripheral airway mechanics and ventilation distribution, suggesting potential physiological benefits beyond skeletal muscle conditioning.

However, because the study lacked a control group, the findings cannot establish that exercise directly caused the observed changes. Further controlled studies are needed to confirm the results and determine whether improvements in IOS measures translate into meaningful long-term clinical benefits.

Reference

Cederberg A et al. Improvement in peripheral airway function after a 12-week exercise intervention in COPD. Respir Res 27, 394 (2026). https://doi.org/10.1186/s12931-026-03933-7