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H. Demeyer

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Open access Aug 2026

The relation between physical activity and cardiac autonomic dysfunction in patients with chronic obstructive pulmonary disease

Background Cardiac autonomic dysfunction is common in patients with chronic obstructive pulmonary disease (COPD). Although exercise training improves cardiac autonomic function, the effects of changing physical activity on cardiac autonomic function remain unknown. Objective This study aimed to (1) investigate the association between cardiac autonomic function, exercise capacity and physical activity cross-sectionally and (2) relate changes in physical activity, as a result of a 6-month coaching program, to changes in cardiac autonomic function. Methods Autonomic function was assessed objectively using the Polar H10 sensor, measuring (1) resting heart rate during sleep; (2) heart rate variability (SDNN, RMSSD, LF/HF ratio and SD2/SD1 ratio) during sleep and (3) heart rate recovery following the 6-minute walking test (6MWT), and subjectively using the COMPASS 31 questionnaire at baseline and 6-months follow-up. Physical activity (steps per day and movement intensity during walking) was measured using accelerometery. Cross-sectional and longitudinal associations were evaluated. Results In 36 patients with COPD (69% male, mean ± SD age 69 ± 7 years, FEV1 53 ± 13%pred, 28% taking β-blockers), baseline cross-sectional analyses showed weak to moderate associations between heart rate recovery and movement intensity during walking (rs = 0.45) and distance covered during 6MWT (rs = 0.55). Longitudinal analyses over 6-months follow-up showed that changes in daily step count were inversely associated with changes in resting heart rate (rs = −0.48), LF/HF ratio (rs = −0.35) and SD2/SD1 ratio (rs = −0.28) and that changes in movement intensity during walking were inversely associated with changes in SD2/SD1 ratio (rs = −0.51) in patients not taking β-blockers. Conclusion Weak cross-sectional associations were observed between certain parameters of cardiac autonomic function, exercise capacity and physical activity. Increasing the amount of physical activity showed a weak relation with lowering resting heart rate over 6 months in patients not taking influencing medication.

F. Hermans, E. Arents, A. Blondeel et al. · PLoS ONE · 0 citations

Open access Jul 2026

Longitudinal associations of physical activity with disease burden in people with COPD

Physical activity levels are reduced in people with chronic obstructive pulmonary disease (COPD). The factors underpinning this, and its impact on individuals’ health, are complex. Our aim was to investigate whether within-person changes in physical activity are associated with subsequent health outcomes, encompassing six-minute walk distance, quadriceps strength, lung function, perceived fatigue (FACIT-F), and symptom burden (CAT). In this multicentre cohort study, 565 individuals with COPD (37% female; age 68±8 years; FEV 1 54±21%pred) were followed over two years, with study visits every six months. Physical activity was assessed using wearable devices (Axivity AX6 or DynaPort MoveMonitor MM+), capturing daily step count and movement intensity during walking. Linear mixed-effects models assessed the longitudinal changes in physical activity and health outcomes, and the associations of within-person changes in physical activity and subsequent health outcomes. Participants showed a significant annual decline of 229 (95%CI 132–326) steps/day. Correcting for baseline PA, each 1000-step annual decline was associated with a 5.13 m (95%CI 3.20–7.06) lower six-minute walk distance, 0.37%pred (95%CI 0.08–0.66) lower FEV 1 , and 0.47-point (95%CI 0.20–0.75) lower FACIT-F at the end of that year. Similar associations were observed for movement intensity as exposure. Only movement intensity was associated with functional quadriceps strength, with each 0.1 m·s −2 decline resulting in a 0.18 s (95%CI 0.35–0.01) slower five-times sit-to-stand performance. No associations were found with the CAT. Within-person decline in physical activity is associated with lower lung function, reduced exercise capacity, increased fatigue symptoms and lower functional quadriceps strength.

Paulien Mellaerts, H. Demeyer, C. Becker et al. · ERJ Open Research · 0 citations