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COPD impairs quadriceps endurance

Patients with COPD exhibited reduced quadriceps endurance when compared with healthy control participants regardless of the type of task or measurement technique, according to study results.

“Most of these studies reported a reduced endurance time or a faster decline in contractile force in individuals with COPD compared with healthy control subjects,” Rachel A. Evans, MBChB, PhD, department of respiratory medicine, Glenfield Hospital in England, and colleagues wrote.

Evans and colleagues conducted a systematic review of studies comparing quadriceps endurance in patients with COPD, most of whom had moderate to severe disease, and endurance in healthy control participants. Relevant studies from 1946-2011 were identified by searching PubMed, Embase, Cinahl, The Cochrane Library and two other databases.

Data were drawn from 21 studies; 728 patients had COPD, and there were 440 healthy controls.

Quadriceps endurance was diminished in patients with COPD compared with healthy controls (standard mean difference = 1.16; 95% CI, 1.02-1.3).

Five of the reviewed studies employed magnetic stimulation to participants’ femoral nerve. The mean duration for individuals with COPD (n = 199) was 87 seconds; the mean duration for healthy controls (n = 110) was 107 seconds.

The researchers said patients with COPD should exercise more to improve oxygen uptake.

“The results of this synthesis show that muscle endurance in COPD is reduced, highlighting the need for the inclusion of muscle-specific training, such as one-legged cycling, in improving peak oxygen uptake in COPD,” the researchers wrote. “Our findings have implications for the development of pharmacologic and nonpharmacologic therapies targeted at improving skeletal muscle endurance.” –by Ryan McDonald

Disclosure: The researchers report no relevant financial disclosures.