Effect of Eccentric Cycling on Oxygen Uptake and Hemodynamics in Patients with Chronic Obstructive Pulmonary Disease: A Randomized Controlled Crossover Trial.

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide and contributes significantly to reduced quality of life due to symptoms such as dyspnea and exercise intolerance. Eccentric cycling exercise (ECC) has shown potential as an alternative to conventional concentric cycling exercise (CON) in cardiopulmonary disease, including COPD, as it has a lower metabolic demand and potentially allows for higher exercise intensity with less perceived exertion. We aimed to compare ventilatory and circulatory responses of COPD patients between ECC and CON at identical submaximal workloads.

METHODS

In a randomized-controlled crossover trial, 17 COPD patients (6 female, mean ± SD age 67 ± 7 years) completed identical submaximal stepwise incremental cycling tests using ECC and CON, each step increasing by 10 W. The main outcome was oxygen uptake (<mml:math id="m1" xmlns:mml="http://www.w3.org/1998/Math/MathML">mml:mrow<mml:mover accent="true"><mml:mi mathvariant="normal">Vmml:mo˙mml:msub<mml:mi mathvariant="normal">Omml:mn2). Additional outcomes were breath-by-breath ergospirometric measurements including minute ventilation (<mml:math id="m2" xmlns:mml="http://www.w3.org/1998/Math/MathML">mml:mrow<mml:mover accent="true"><mml:mi mathvariant="normal">Vmml:mo˙<mml:mi mathvariant="normal">E) and hemodynamics by echocardiography at each step.

RESULTS

At a mean end-exercise intensity of 41.3 ± 3.5 W, ECC lowered <mml:math id="m3" xmlns:mml="http://www.w3.org/1998/Math/MathML">mml:mrow<mml:mover accent="true"><mml:mi mathvariant="normal">Vmml:mo˙mml:msub<mml:mi mathvariant="normal">Omml:mn2 by -122 mL/min (-25%, 95% CI: -213 to -47, p = 0.005) and <mml:math id="m4" xmlns:mml="http://www.w3.org/1998/Math/MathML">mml:mrow<mml:mover accent="true"><mml:mi mathvariant="normal">Vmml:mo˙<mml:mi mathvariant="normal">E by -5.7 L/min (-29%, 95% CI: -10.0 to -1.6, p = 0.012) compared to CON. Perceived dyspnea and leg fatigue did not differ. A trend toward reduced strain on the right ventricle was observed in ECC (37 ± 13 mm Hg ECC vs. 48 ± 7 mm Hg CON), but this was not significant (p = 0.063). No adverse events occurred.

CONCLUSION

ECC allowed COPD patients to exercise at the same workload but with a lower metabolic and ventilatory demand compared to CON, suggesting it has the potential to further improve exercise capacity in pulmonary rehabilitation.